Details of the Researcher

PHOTO

Hitoshi Soyama
Section
Graduate School of Engineering
Job title
Professor
Degree

  • 工学博士（東北大学）

Profile
機械系表面改質研究センター,センター長
キャビテーションピーニングの概要：https://youtu.be/BurRGrmOGQY

Research History 4

  • 2003/04 - Present
    Tohoku University　Professor

  • 1997/04 - 2003/03
    東北大学 助教授(工学研究科) 大学院重点化による配置換

  • 1995/10 - 1997/03
    東北大学 助教授(工学部)

  • 1991/04 - 1995/09
    東北大学 助手(流体科学研究所)

Education 2

  • Tohoku University　Graduate School, Division of Engineering　機械工学

    - 1991/03/28

  • Tohoku University　Faculty of Engineering　機械工学科

    - 1986/03/25

Committee Memberships 20

  • SAE International, Surface Enhancement Committee SEC　Member

    2014/01 - Present

  • SAE International, Aerospace Metals Engineering Committee, Surface Enhancement Subcommittee AMEC-SE　Member

    2013/08 - Present

  • ASTM Intenational, G02.10 Sub-committee, Task group of ASTM G134 ILS　Chairman

    2010/08 - Present

  • ショットピーニング技術協会　理事

    2007/06 - Present

  • 日本混相流学会　会長

    2021/08 - 2022/08

  • 日本混相流学会　副会長

    2020/08 - 2021/08

  • 自動車技術会東北支部　幹事

    2010/05 - 2018/05

  • 日本機械学会東北支部　幹事（表彰担当）

    2015/03 - 2017/03

  • 日本ウォータージェット学会　会長

    2014/05 - 2016/06

  • 自動車技術会東北支部　支部長

    2014/05 - 2016/05

  • 自動車技術会東北支部　支部長

    2014/05 - 2016/05

  • 自動車技術会　理事

    2014/05 - 2016/05

  • 日本ウォータージェット学会　副会長

    2010/04 - 2014/05

  • 日本ウォータージェット学会　理事

    2004/04 - 2014/05

  • 日本機械学会東北支部　幹事（企画担当）

    2013/03 - 2014/03

  • 自動車技術会東北支部学生自動車研究会　参与

    2010/05 - 2013/05

  • 自動車技術会東北支部学生自動車研究会　参与

    2010/05 - 2013/05

  • 日本材料学会　理事

    2004/05 - 2006/05

  • 日本材料学会 東北支部　支部長

    2004/05 - 2006/05

  • 日本材料学会 東北支部　支部長

    2004/05 - 2006/05

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Professional Memberships 11

  • Japan Society of Sonochemistry

    2024/01 - Present

  • Society of Automotive Engineers of Japan, Inc

  • The Japan Society of Multiphase Flow

  • ショットピーニング技術協会

  • 日本材料学会

  • 日本ウォータージェット学会

  • 日本機械学会

  • SAE International

  • 日本工学アカデミー

  • ASTM International

  • American Society of Mechanical Engineers

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Research Interests 3

  • Cavitation

  • Surface Mechanics

  • Surface modification

Research Areas 3

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Fluid engineering / Cavitation

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Manufacturing and production engineering / Surface modification

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Machine materials and mechanics / 水素脆化抑止

Awards 24

  1. Awards for Science and Technology (Research Category)

    2024/04　The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology　Surface mechanics design of materials by using liquid-gas phase change phenomenon

  2. フェロー

    2019/06　公益社団法人自動車技術会

  3. 日本材料学会支部功労賞

    2017/05/27　日本材料学会　機械的表面改質による表面力学設計に関する研究ならびに日本材料学会東北支部に関する貢献

  4. 自動車技術会功労者

    2017/05/25　自動車技術会

  5. ASME Fellow

    2016/01/26　American Society of Mechanical Engineers

  6. 日本ウォータージェット学会功労賞

    2015/05/29　一般社団法人日本ウォータージェット学会

  7. 日本材料学会学術貢献賞

    2015/05/23　日本材料学会　機械的表面改質による金属材料の疲労強度向上に関する研究と材料学会活動への貢献

  8. 日本機械学会フェロー

    2015/01/13　日本機械学会

  9. Fluids Science Research Award

    2014/10/09　一般財団法人機器研究会　キャビテーション噴流の加工能力向上と機械的表面改質による金属材料疲労強度向上への適用

  10. (Best Paper Award of the Water Jet Technology Society of Japan)

    2013/05/24　一般社団法人日本ウォータージェット学会　水噴流加速式循環型ショットピーニングによるステンレス鋼の水素脆化抑止

  11. 市村学術賞功績賞

    2013/04/25　公益財団法人新技術開発財団　サステイナブル表面改質のためのキャビテーションピーニングの開発

  12. 日本ウォータージェット学会技術賞

    2008/05/23　日本ウォータージェット学会　次世代キャビテーション・ピーニング装置の開発

  13. 創立20周年記念功績賞

    2007/12/01　財団法人天田金属加工機械技術振興財団　キャビテーション噴流式ハイブリッド表面改質法の開発

  14. 日本機械学会賞（論文）

    2007/04/06　日本機械学会　Cavitation Shotless Peening for Surface Modification of Alloy Tool Steel

  15. 第56回自動車技術会賞論文賞

    2006/05/25　社団法人自動車技術会　キャビテーション・ショットレス・ピーニングによる金属材料の疲労強度向上

  16. 日本ウォータージェット学会論文賞

    2003/05/16　日本ウォータージェット学会　Possibility of Gettering in Silicon Wafer by Using a Cavitating Jet

  17. 財団法人トーキン科学技術振興財団研究奨励賞最優秀賞

    2003/03/24　財団法人トーキン科学技術振興財団　次世代キャビテーション・ショットレス・ピーニングの構築

  18. 日本ウォータージェット学会論文賞(Best Paper Award of the Water Jet Technology Society of Japan)

    2001/04/20　日本ウォータージェット学会(The Water Jet Technology Society of Japan)　キャビテーション衝撃力の利用による水噴流の加工能力の増大とその機械材料のピーニングへの利用

  19. 日本機械学会東北支部技術研究賞(JSME Tohoku Branch Science and Technology Award)

    2001/03/10　日本機械学会東北支部(Tohoku Branch, JSME)　キャビテーション噴流式ハイブリッド表面改質装置の開発研究(Research on Hybrid Surface Modification System by Using a Cavitating Jet)

  20. 日本混相流学会賞奨励賞 (Award for Young Engineers)

    2000/07/13　日本混相流学会 (Japanese Society for Multiphase Flow)　キャビテーション噴流による炭素鋼の耐食性向上に関する研究

  21. チャレンジ大賞(Award for Challengers)

    1998/08/06　ターボ機械協会(Turbomachinery Society of Japan)　表面改質へのキャビテーション噴流の有効利用(Practical Use of Cavitating Jet to Surface Modification)

  22. JSME Award for Young Engineers, Research

    1995/04/01　日本機械学会 (Japan Society of Mechanical Engineers)　激しいキャビテーション壊食の挙動とその有効利用に関する研究(A Study on Severe Cavitation Erosion and Its Application)

  23. ターボ機械協会賞論文賞 (Turbomachinery Medal for the Best Papers)

    1991/05/16　ターボ機械協会 (Turbomachinery Society of Japan)　遠心ポンプにおける激しいキャビテーション壊食の発達過程（第１報及び第２報）(Severe Erosion Progress in a Typical Centrifugal Pump)

  24. 研究奨励賞 (Award for Young Engineers)

    1991/01/04　財団法人機器研究会 (Association for Fluid Sientists)　キャビテーションノイズの寸法効果に関する研究(A Study on Scaling Effect of Cavitation Noise)

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Papers 325

  1. Development of MHz X-ray phase contrast imaging at the European XFEL International-coauthorship Peer-reviewed

    Jayanath C. P. Koliyadu, Daniel Moško, Eleni Myrto Asimakopoulou, Valerio Bellucci, Šarlota Birnšteinová, Richard Bean, Romain Letrun, Chan Kim, Henry Kirkwood, Gabriele Giovanetti, Nerea Jardon, Janusz Szuba, Trey Guest, Andreas Koch, Jan Grünert, Peter Szeles, Pablo Villanueva-Perez, Fabian Reuter, Claus-Dieter Ohl, Mike Andreas Noack, Francisco Garcia-Moreno, Zuzana Kuglerová-Valdová, Libor Juha, Martin Nikl, Wataru Yashiro, Hitoshi Soyama, Daniel Eakins, Alexander M. Korsunsky, Jozef Uličný, Alke Meents, Henry N. Chapman, Adrian P. Mancuso, Tokushi Sato, Patrik Vagovič

    Journal of Synchrotron Radiation　32　(1)　2025/01/01

    Publisher: International Union of Crystallography (IUCr)

    DOI： 10.1107/s160057752400986x 　

    eISSN： 1600-5775

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    We report on recent developments that enable megahertz hard X-ray phase contrast imaging (MHz XPCI) experiments at the Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX) instrument of the European XFEL facility (EuXFEL). We describe the technical implementation of the key components, including an MHz fast camera and a modular indirect X-ray microscope system based on fast scintillators coupled through a high-resolution optical microscope, which enable full-field X-ray microscopy with phase contrast of fast and irreversible phenomena. The image quality for MHz XPCI data showed significant improvement compared with a pilot demonstration of the technique using parallel beam illumination, which also allows access to up to 24 keV photon energies at the SPB/SFX instrument of the EuXFEL. With these developments, MHz XPCI was implemented as a new method offered for a broad user community (academic and industrial) and is accessible via standard user proposals. Furthermore, intra-train pulse diagnostics with a high few-micrometre spatial resolution and recording up to 128 images of consecutive pulses in a train at up to 1.1 MHz repetition rate is available upstream of the instrument. Together with the diagnostic camera upstream of the instrument and the MHz XPCI setup at the SPB/SFX instrument, simultaneous two-plane measurements for future beam studies and feedback for machine parameter tuning are now possible.

  2. Investigation of surface finish and fatigue life of laser Powder Bed fused Ti-6Al-4V International-coauthorship Peer-reviewed

    Kannan Pradeep Varsha, Swee-Hock Yeo, Hitoshi Soyama

    International Journal of Fatigue　189　108558-108558　2024/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.ijfatigue.2024.108558 　

    ISSN： 0142-1123

  3. Non-Spherical Cavitation Bubbles: A Review Invited Peer-reviewed

    Boxin Jia, Hitoshi Soyama

    Fluids　9　(11)　249-249　2024/10/25

    Publisher: MDPI AG

    DOI： 10.3390/fluids9110249 　

    eISSN： 2311-5521

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    Cavitation is a phase-change phenomenon from the liquid to the gas phase due to an increased flow velocity. As it causes severe erosion and noise, it is harmful to hydraulic machinery such as pumps, valves, and screw propellers. However, it can be utilized for water treatment, in chemical reactors, and as a mechanical surface treatment, as radicals and impacts at the point of cavitation bubble collapse can be utilized. Mechanical surface treatment using cavitation impacts is called “cavitation peening”. Cavitation peening causes less pollution because it uses water to treat the mechanical surface. In addition, cavitation peening improves on traditional methods in terms of fatigue strength and the working life of parts in the automobile, aerospace, and medical fields. As cavitation bubbles are utilized in cavitation peening, the study of cavitation bubbles has significant value in improving this new technique. To achieve this, many numerical analyses combined with field experiments have been carried out to measure the stress caused by bubble collapse and rebound, especially when collapse occurs near a solid boundary. Understanding the mechanics of bubble collapse can help to avoid unnecessary surface damage, enabling more accurate surface preparation, and improving the stability of cavitation peening. The present study introduces three cavitation bubble types: single, cloud, and vortex cavitation bubbles. In addition, the critical parameters, governing equations, and high-speed camera images of these three cavitation bubble types are introduced to support a broader understanding of the collapse mechanism and characteristics of cavitation bubbles. Then, the results of the numerical and experimental analyses of non-spherical cavitation bubbles are summarized.

  4. Improvement of Fatigue Strength in Additively Manufactured Aluminum Alloy AlSi10Mg via Submerged Laser Peening Invited Peer-reviewed

    Hitoshi Soyama

    Coatings　14　(9)　1174-1174　2024/09/11

    Publisher: MDPI AG

    DOI： 10.3390/coatings14091174 　

    eISSN： 2079-6412

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    As the fatigue properties of as-built components of additively manufactured (AM) metals are considerably weaker than those of wrought metals because of their rougher surface, post-processing is necessary to improve the fatigue properties. To demonstrate the improvement in the fatigue properties of AM metals via post-processing methods, the fabrication of AlSi10Mg, i.e., PBF–LS/AlSi10Mg, through powder bed fusion (PBF) using laser sintering (LS) and its treatment via submerged laser peening (SLP), using a fiber laser and/or a Nd/YAG laser, was evaluated via plane bending fatigue tests. In SLP, laser ablation (LA) is generated by a pulsed laser and a bubble is generated after LA, which behaves like a cavitation bubble that is referred to as “laser cavitation (LC)”. In this paper, LA-dominated SLP is referred to as “laser treatment (LT)”, while LC collapse-dominated SLP is referred to as “laser cavitation peening (LCP)”, as the impact of LC collapse is used for peening. It was revealed that SLP using a fiber laser corresponded with LT rather than LCP. It was demonstrated that the fatigue strength at N = 107 was 85 MPa for LCP and 103 MPa for the combined process of blasting (B) + LT + LCP, whereas the fatigue strength of the as-built specimen was 54 MPa.

  5. The effects of submerged laser peening, cavitation peening, and shot peening on the improvement of the torsional fatigue strength of powder bed fused Ti6Al4V produced through laser sintering International-journal International-coauthorship Peer-reviewed

    Hitoshi Soyama, Kwan Lok Wong, Daniel Eakins, Alexander M. Korsunsky

    International Journal of Fatigue　185　108348-108348　2024/08

    Publisher: Elsevier BV

    DOI： 10.1016/j.ijfatigue.2024.108348 　

    ISSN： 0142-1123

  6. Defect dynamics studies during heat treatments in plastically deformed metals predicted for nuclear applications International-journal International-coauthorship

    Krzysztof Siemek, Hitoshi Soyama, Mirosław Wróbel, Maciej Oskar Liedke, Maik Butterling, Andreas Wagner, Mariusz Kulczyk, Paweł Horodek

    Journal of Materials Research　2024/06/14

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1557/s43578-024-01363-z 　

    ISSN： 0884-2914

    eISSN： 2044-5326

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    Abstract We report on defects dynamics during heat treatment in plastically deformed metallic materials using positron annihilation lifetime spectroscopy carried out on the intense pulsed positron beam. The conducted experiment allowed us to observe the changes in the concentration and sizes of vacancy-like defects observed during in situ annealing. We monitored heat treatments up to 300 °C in hydrostatic extruded Ti and cavitation peened V–4Cr–4Ti alloy. We were able to track the recovery processes in Ti and redistribution of large voids at the surface of cavitation peened V–4Cr–4Ti alloy. The relaxation time during recovery was about 20 min. Performed experiments show that in cold-worked metallic materials significant changes in vacancy clusters concentrations occur at mildly elevated temperatures. The presented results give opportunity to the application of in situ observation of defects dynamic to similar problems related to thermomechanical processing of metallic materials. Graphical abstract

  7. Differences in Cavitation Erosion Test Methods for Development of Anti-Cavitation Cylinder Liner Peer-reviewed

    Takashi SATO, Yuki KUROMASA, Koichi HATAKEYAMA, Hitoshi SOYAMA

    Turbomachinery　52　(5)　300-307　2024/05/10

    Publisher: Turbomachinery Society of Japan

  8. Improvement of Fatigue Strength of 3D-Metal by Combined Process of Blasting and Cavitation Peening International-journal Peer-reviewed

    Hitoshi Soyama

    Lecture Notes in Mechanical Engineering　23-29　2024/05/07

    Publisher: Springer Nature Singapore

    DOI： 10.1007/978-981-99-8643-9_3 　

    ISSN： 2195-4356

    eISSN： 2195-4364

  9. Fluid/Material Coupled Numerical Simulation of a Bubble Collapse Near a Wall for Laser Cavitation Peening International-journal Invited Peer-reviewed

    Yuka Iga, Chieko Kuji, Hirotoshi Sasaki, Hitoshi Soyama

    Lecture Notes in Mechanical Engineering　309-314　2024/05/07

    Publisher: Springer Nature Singapore

    DOI： 10.1007/978-981-99-8643-9_37 　

    ISSN： 2195-4356

    eISSN： 2195-4364

  10. Development of a Cavitation Generator Mimicking Pistol Shrimp International-journal Invited Peer-reviewed

    Hitoshi Soyama, Mayu Tanaka, Takashi Takiguchi, Matsuo Yamamoto

    Biomimetics　9　(1)　47-47　2024/01/12

    Publisher: MDPI AG

    DOI： 10.3390/biomimetics9010047 　

    eISSN： 2313-7673

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    Pistol shrimp generate cavitation bubbles. Cavitation impacts due to bubble collapses are harmful phenomena, as they cause severe damage to hydraulic machinery such as pumps and valves. However, cavitation impacts can be utilized for mechanical surface treatment to improve the fatigue strength of metallic materials, which is called “cavitation peening”. Through conventional cavitation peening, cavitation is generated by a submerged water jet, i.e., a cavitating jet or a pulsed laser. The fatigue strength of magnesium alloy when treated by the pulsed laser is larger than that of the jet. In order to drastically increase the processing efficiency of cavitation peening, the mechanism of pistol shrimp (specifically when used to create a cavitation bubble), i.e., Alpheus randalli, was quantitatively investigated. It was found that a pulsed water jet generates a cavitation bubble when a shrimp snaps its claws. Furthermore, two types of cavitation generators were developed, namely, one that uses a pulsed laser and one that uses a piezo actuator, and this was achieved by mimicking a pistol shrimp. The generation of cavitation bubbles was demonstrated by using both types of cavitation generators: the pulsed laser and the piezo actuator.

  11. Revealing the origins of vortex cavitation in a Venturi tube by high speed X-ray imaging International-journal International-coauthorship Peer-reviewed

    Hitoshi Soyama, Xiaoyu Liang, Wataru Yashiro, Kentaro Kajiwara, Eleni Myrto Asimakopoulou, Valerio Bellucci, Sarlota Birnsteinova, Gabriele Giovanetti, Chan Kim, Henry J. Kirkwood, Jayanath C.P. Koliyadu, Romain Letrun, Yuhe Zhang, Jozef Uličný, Richard Bean, Adrian P. Mancuso, Pablo Villanueva-Perez, Tokushi Sato, Patrik Vagovič, Daniel Eakins, Alexander M. Korsunsky

    Ultrasonics Sonochemistry　101　106715-106715　2023/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.ultsonch.2023.106715 　

    ISSN： 1350-4177

  12. 2D X-ray diffraction method for evaluating the local crystallization of Fe-based amorphous alloy ribbon induced by ultrashort pulsed laser local heating International-journal Peer-reviewed

    Chieko Kuji, Masayoshi Mizutani, Tsunemoto Kuriyagawa, Hitoshi Soyama

    Materials Today Communications　37　107166-107166　2023/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.mtcomm.2023.107166 　

    ISSN： 2352-4928

  13. Development of Laser Cavitation Peening Using a Normal-Oscillation Nd:YAG Laser International-journal Invited Peer-reviewed

    Hitoshi Soyama

    Coatings　13　(8)　1395-1395　2023/08/08

    Publisher: MDPI AG

    DOI： 10.3390/coatings13081395 　

    eISSN： 2079-6412

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    The impact induced by cavitation bubble collapse can be utilized for mechanical surface treatment to improve fatigue properties of metals including additive manufactured metallic materials. A peening method using cavitation impact induced by a pulsed laser is called “laser cavitation peening (LCP)”. Normally, a Q-switched Nd:YAG laser, whose pulse width is a few nanoseconds, is used for LCP, which improves the fatigue strength. The problem with LCP is that the processing time is too slow. If a laser pulse whose pulse width is a few hundred microseconds can be utilized for LCP, the repetition frequency can be increased drastically using other types of laser systems such as a fiber laser. In the present paper, in order to reveal the possibility of LCP using a pulsed laser width of a few hundred microseconds, the use of LCP with a normal-oscillation Nd:YAG laser (pulse width ≈ 200 μs) was investigated. It is demonstrated that LCP with the normal-oscillation Nd:YAG laser produced curvature in an aluminum alloy plate. The shock pressure wave and impulsive vibration of the target surface at the first collapse of laser cavitation (LC), which was induced by the normal-oscillation Nd:YAG laser, was 3–4 times larger than those of laser ablation (LA).

  14. Experimental study on the effect of the milling condition of an aluminum alloy on subsurface residual stress International-journal International-coauthorship Peer-reviewed

    Chieko Kuji, Christopher R. Chighizola, Michael R. Hill, Jan C. Aurich, Hitoshi Soyama

    The International Journal of Advanced Manufacturing Technology　2023/07/14

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s00170-023-11921-0 　

    ISSN： 0268-3768

    eISSN： 1433-3015

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    Abstract Aluminum alloys used in monolithic parts for aerospace applications are subjected to distortion and residual stress (RS) generated by milling, affecting the product fatigue life. Particularly, the change in RS with depth (z) has a characteristic distribution with a maximum compressive RS at a z several tens of micrometers from the surface; however, the RS value depends on the measurement method used. In this study, the RS distribution with z from the surface after milling was measured for the AA7050-T7451 aluminum alloy by two-dimensional X-ray diffraction (2D method). The results were compared with those of four prior measurement methods, and the validity of 2D method was verified. The changes in subsurface RS with z showed similar distributions under all measurement conditions except when cos(α)-XRD was employed. The 2D method provides high repeatability. The in-plane RS distribution was also measured using 2D method to investigate the effect of milling conditions on this distribution. The RS values varied markedly depending on the measurement position, particularly at a small collimator diameter of 0.146 mm, allowing detection of localized extreme RS values. The maximum RS at z = 0 mm was − 85.6 MPa at a cutting speed of vc = 200 m/s and feed per tooth of fz = 0.05 mm, while it was − 16 MPa for vc = 450 m/s and 6.8 MPa for fz = 0.2 mm, revealing that the compressive RS changes to tensile RS as vc and fz increase.

  15. Laser Cavitation Peening: A Review International-journal Invited Peer-reviewed

    Hitoshi Soyama, Yuka Iga

    Applied Sciences　13　(11)　6702-6702　2023/05/31

    Publisher: MDPI AG

    DOI： 10.3390/app13116702 　

    eISSN： 2076-3417

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    During submerged laser peening using a pulsed laser, a bubble that behaves like cavitation is generated after laser ablation (LA). The bubble is referred to as laser cavitation (LC). The amplitude of the shockwave in water generated by LA is larger than that of LC; however, the impact passing through the target metal during LC is larger than that of LA. LC impact can be utilized for peening at optimized conditions. Thus, submerged laser peening is referred to as “laser cavitation peening”, as the peening method using the cavitation impact is known as “cavitation peening”. The impact induced by a hemispherical bubble is more aggressive than that of a spherical bubble with a microjet. Laser cavitation peening can improve the fatigue strength of metallic materials by producing work-hardening and introducing compressive residual stress. Three-dimensional additively manufactured metals (3D metals) such as titanium alloy are attractive materials for aviation components and medical implants; however, the fatigue strength of as-built components is nearly half of that of bulk metals, and this is an obstacle for the applications of 3D metals. In the present study, published research papers are reviewed to identify the key factors of laser cavitation peening, with additional visualization of LC and data. Then, improvements in the fatigue strength of metallic materials, including 3D metals treated by laser cavitation peening, are summarized.

  16. Comparison of the effects of submerged laser peening, cavitation peening and shot peening on the improvement of the fatigue strength of magnesium alloy AZ31 International-journal International-coauthorship Peer-reviewed

    Hitoshi Soyama, Chieko Kuji, Yiliang Liao

    Journal of Magnesium and Alloys　11　(5)　1592-1607　2023/05

    Publisher: Elsevier BV

    DOI： 10.1016/j.jma.2023.04.004 　

    ISSN： 2213-9567

  17. Effect of local heating by ultrashort pulsed laser on Fe–Si–B–Cr amorphous alloys and its influence on blanking machinability Peer-reviewed

    Chieko Kuji, Masayoshi Mizutani, Kana Takenaka, Keita Shimada, Toyohiko J. Konno, Hitoshi Soyama, Tsunemoto Kuriyagawa

    Precision Engineering　81　135-144　2023/05

    Publisher: Elsevier BV

    DOI： 10.1016/j.precisioneng.2023.02.007 　

    ISSN： 0141-6359

  18. Fabrication of temperature-selective thermal radiation surfaces utilizing surface texturing Peer-reviewed

    Chieko Kuji, Masayuki Ishii, Ryuichi Yoshikawa, Masayoshi Mizutani, Hitoshi Soyama

    Precision Engineering　2023/03

    Publisher: Elsevier BV

    DOI： 10.1016/j.precisioneng.2023.03.003 　

    ISSN： 0141-6359

  19. Mechanical Surface Treatment of Titanium Alloy Ti6Al4V Manufactured by Direct Metal Laser Sintering Using Laser Cavitation International-journal Invited Peer-reviewed

    Chieko Kuji, Hitoshi Soyama

    Metals　13　(1)　181-181　2023/01/16

    Publisher: MDPI AG

    DOI： 10.3390/met13010181 　

    eISSN： 2075-4701

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    Additive manufactured (AM) metals are attractive materials for medical implants, as their geometries are directly produced from computer-aided design (CAD)/computer-aided manufacturing (CAM) data. However, the fatigue properties of AM metals are weak compared with bulk metals, which is an obstacle to the practical applications of AM metals. To improve the fatigue properties of AM metals, we developed a mechanical surface treatment using laser cavitation. When we irradiate a pulsed laser to a metallic surface in water, laser ablation is generated, and a bubble that behaves like a cavitation is produced. The bubble is referred to as a “laser cavitation”. In the surface treatment using laser cavitation, we use the plastic deformation caused by the impact force at the bubble collapse and pulsed laser energy that produces local melting at the same time. Thus, the mechanical surface treatment using laser cavitation is a type of surface mechanical alloying. In this study, to demonstrate the improvement in the fatigue properties of AM metals, we treated titanium alloy Ti6Al4V, which was manufactured by direct metal laser sintering (DMLS), with laser cavitation, and we evaluated the surface morphology, roughness, residual stress, hardness, and finally tested it using a torsion fatigue test. Unmelted particles on the DMLS surface, which cause fatigue cracks, were melted and resolidified using laser cavitation, resulting in a reduction of the maximum heights of roughness (Rz) of about 75% and the arithmetical mean roughness (Ra) of about 84% of the non-peened one. Although tensile residual stresses of about 80–180 MPa were generated on the as-built surface, compressive residual stresses of about −80 MPa were introduced by laser cavitation. Furthermore, laser cavitation formed Ti4O5 oxide film, which increased the surface hardness by about 106%. Finally, we performed torsional fatigue tests and revealed that laser cavitation extended the fatigue life from 19,791 cycles to 36,288 cycles at an applied shear stress (τa) at 460 MPa, which is effective in suppressing crack initiation.

  20. Improvement of Fatigue Properties of Metallic Materials by Peening Methods Using a Water Jet Invited Peer-reviewed

    Hitoshi Soyama

    Proceedings of 13th Pacific Rim International Conference on Water Jet Technology (PRIC2022)　1-5　2022/11

    Publisher: Water Jet Technology Society of Japan

  21. Improving effects of cavitation peening, using a pulsed laser or a cavitating jet, and shot peening on the fatigue properties of additively manufactured titanium alloy Ti6Al4V International-journal Peer-reviewed

    Hitoshi Soyama, Chieko Kuji

    Surface and Coatings Technology　129047-129047　2022/11

    Publisher: Elsevier BV

    DOI： 10.1016/j.surfcoat.2022.129047 　

    ISSN： 0257-8972

  22. Mechanical surface treatment studies by Bragg edge neutron imaging International-coauthorship Peer-reviewed

    Ranggi S. Ramadhan, Daniel Glaser, Hitoshi Soyama, Winfried Kockelmann, Takenao Shinohara, Thilo Pirling, Michael E. Fitzpatrick, Anton S. Tremsin

    Acta Materialia　239　118259-118259　2022/10

    Publisher: Elsevier BV

    DOI： 10.1016/j.actamat.2022.118259 　

    ISSN： 1359-6454

  23. Cavitation Peening Using a Submerged Water Jet and a Pulsed Laser Comparing with Shot Peening International-journal Invited Peer-reviewed

    Hitoshi Soyama

    Proceedings of 14th International conference on Shot Peening ICSP14　89　2022/09

  24. A critical comparative review of cavitation peening and other surface peening methods International-journal International-coauthorship Peer-reviewed

    Hitoshi Soyama, Alexander M. Korsunsky

    Journal of Materials Processing Technology　305　117586-117586　2022/07

    Publisher: Elsevier BV

    DOI： 10.1016/j.jmatprotec.2022.117586 　

    ISSN： 0924-0136

  25. Combination of Laser Shock Peening with Cavitation, Shot, and Ultrasonic Impact Hardening for Stainless Steels Surface Characteristics Improving International-coauthorship Peer-reviewed

    D. A. Lesyk, H. Soyama, B. N. Mordyuk, O. Stamann, V. V. Dzhemelinskyi

    METALLOFIZIKA I NOVEISHIE TEKHNOLOGII　44　(1)　79-95　2022/04/04

    Publisher: National Academy of Sciences of Ukraine (Co. LTD Ukrinformnauka) (Publications)

    DOI： 10.15407/mfint.44.01.0079 　

    ISSN： 1024-1809

    eISSN： 1024-1809

  26. Improvement of Fatigue Characteristics of Welded Parts by Cavitation Peening Invited Peer-reviewed

    Hitoshi SOYAMA

    JOURNAL OF THE JAPAN WELDING SOCIETY　91　(3)　195-199　2022/03

    Publisher: Japan Welding Society

    DOI： 10.2207/jjws.91.195 　

    ISSN： 0021-4787

    eISSN： 1883-7204

  27. Surface integrity of heat treatable magnesium alloy AZ80A after cavitation peening International-journal International-coauthorship Peer-reviewed

    Sebastjan Žagar, Hitoshi Soyama, Janez Grum, Roman Šturm

    Journal of Materials Research and Technology　17　2098-2107　2022/02/02

    Publisher: Elsevier

    DOI： 10.1016/j.jmrt.2022.01.156 　

  28. Effect on improvement of fatigue life of stainless steel using the cavitating jet reinforced by the water flow holes near the nozzle outlet and the long guide pipe Peer-reviewed

    Hirokazu Kamisaka, Hitoshi Soyama

    journal of Jet Flow Engineering　36　(2)　4-15　2021/11/10

    Publisher: The Water Jet Technology Society of Japan

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    Aggressive intensity of cavitating jet depends largely on the nozzle geometry. In the previous report, the aggressive intensity of the advanced nozzle with water flow holes near the outlet of the throat and long guide pipe was compared with that of the standard nozzle, and it was clarified that the aggressive intensity of the advanced nozzle was about 2.5 times higher than that of the standard nozzle. In this study, in order to clarify the effect of these two nozzles on the fatigue life, a plane bending fatigue test of specimens peened using the cavitating jet ejected from these two nozzles was carried out. As a result of the fatigue test, the advanced nozzle was found to provide the same fatigue life as the standard nozzle in 75% of the processing time of the standard nozzle. The surface roughness and hardness of the specimens treated by the advanced nozzle was larger than that of the standard nozzle. In addition, according to the residual stress distribution in depth obtained by repeating X-ray residual stress measuring and electrolytic polishing, the depth at which compressive residual stress was formed was the same for the two nozzles. As the depth of compressive layer corresponded with the impact force, it was concluded that the reduction in processing time with the advanced nozzle was brought about by the increased number of impacts rather than the increase in impact force.

  29. Optimization of Residual Stress Measurement Conditions for a 2D Method Using X-ray Diffraction and Its Application for Stainless Steel Treated by Laser Cavitation Peening International-coauthorship Peer-reviewed

    Hitoshi Soyama, Chieko Kuji, Tsunemoto Kuriyagawa, Christopher R. Chighizola, Michael R. Hill

    Materials　14　(11)　2772-2772　2021/05/24

    Publisher: MDPI AG

    DOI： 10.3390/ma14112772 　

    eISSN： 1996-1944

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    As the fatigue strength of metallic components may be affected by residual stress variation at small length scales, an evaluation method for studying residual stress at sub-mm scale is needed. The sin2ψ method using X-ray diffraction (XRD) is a common method to measure residual stress. However, this method has a lower limit on length scale. In the present study, a method using at a 2D XRD detector with ω-oscillation is proposed, and the measured residual stress obtained by the 2D method is compared to results obtained from the sin2ψ method and the slitting method. The results show that the 2D method can evaluate residual stress in areas with a diameter of 0.2 mm or less in a stainless steel with average grain size of 7 μm. The 2D method was further applied to assess residual stress in the stainless steel after treatment by laser cavitation peening (LCP). The diameter of the laser spot used for LCP was about 0.5 mm, and the stainless steel was treated with evenly spaced laser spots at 4 pulses/mm2. The 2D method revealed fluctuations of LCP-induced residual stress at sub-mm scale that are consistent with fluctuations in the height of the peened surface.

  30. Estimation of Luminescence Intensity of Hydrodynamic Cavitation Considering Sound Velocity in the Cavitating Flow Field Peer-reviewed

    Hitoshi Soyama

    Proceedings of 11th International Symposium on Cavitation　242-245　2021/05

  31. Aspect of Bubbles in Narrow Tube Imitating Root Canal Induced by Er:YAG Laser Peer-reviewed

    Hitoshi Soyama, Yoshio Yahata, Masahiro Saito

    Proceedings of 11th International Symposium on Cavitation　229-232　2021/05

  32. Depth-profiling of residual stress and microstructure for austenitic stainless steel surface treated by cavitation, shot and laser peening International-journal International-coauthorship Peer-reviewed

    Masayoshi Kumagai, Matthew E. Curd, Hitoshi Soyama, Támas Ungár, Gábor Ribárik, Philip J. Withers

    Materials Science and Engineering: A　813　141037-141037　2021/05

    Publisher: Elsevier BV

    DOI： 10.1016/j.msea.2021.141037 　

    ISSN： 0921-5093

  33. Laser Cavitation Peening and Its Application for Improving the Fatigue Strength of Welded Parts Invited Peer-reviewed

    Hitoshi Soyama

    Metals　11　(4)　531-531　2021/03/24

    Publisher: MDPI AG

    DOI： 10.3390/met11040531 　

    eISSN： 2075-4701

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    During conventional submerged laser peening, the impact force induced by laser ablation is used to produce local plastic deformation pits to enhance metallic material properties, such as fatigue performance. However, a bubble, which behaves like a cavitation, is generated after laser ablation, known as “laser cavitation.” On the contrary, in conventional cavitation peening, cavitation is generated by injecting a high-speed water jet into the water, and the impacts of cavitation collapses are utilized for mechanical surface treatment. In the present paper, a mechanical surface treatment mechanism using laser cavitation impact, i.e., “laser cavitation peening”, was investigated, and an improvement in fatigue strength from laser cavitation peening was demonstrated. The impact forces induced by laser ablation and laser cavitation collapse were evaluated with a polyvinylidene fluoride (PVDF) sensor and a submerged shockwave sensor, and the diameter of the laser cavitation was measured by observing a high-speed video taken with a camera. It was revealed that the impact of laser cavitation collapse was larger than that of laser ablation, and the peening effect was closely related to the volume of laser cavitation. Laser cavitation peening improved the fatigue strength of stainless-steel welds.

  34. Use of Cavitation Abrasive Surface Finishing to Improve the Fatigue Properties of Additive Manufactured Titanium Alloy Ti6Al4V International-journal International-coauthorship Peer-reviewed

    Daniel G. Sanders, Hitoshi Soyama, Channa De Silva

    SAE technical paper, AeroTech　2021-01-0024　2021/03

    Publisher: SAE International

    DOI： 10.4271/2021-01-0024 　

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    To improve the fatigue properties of additive manufactured (AM) titanium alloy Ti6Al4V, cavitation abrasive surface finishing (CASF) was proposed. With CASF, a high-speed water jet with cavitation, i.e. a cavitating jet, was injected into a water-filled chamber, to which abrasives were added. Abrasives accelerated by the jet created a smooth surface by removing un-melted particles on the surface. Simultaneously, cavitation impacts induced by the jet introduced compressive residual stress and work hardening into the surface, similar to cavitation peening. In this study, to demonstrate the improvement of the fatigue properties of AM Ti6Al4V owing to CASF, Ti6Al4V specimens manufactured through direct metal laser sintering (DMLS) and electron beam melting (EBM) were treated using CASF and cavitation peening, and tested using a plane bending fatigue test. The fatigue life of the specimen treated using CASF was found to be better than that of an as-built specimen, as CASF made the surface smooth with the introduction of compressive residual stress and work hardening at the same time. The fatigue properties of the specimen treated using cavitation peening after CASF (CASF & cavitation peening) surpassed that of the specimen treated using CASF. The fatigue strength of the AM Ti6Al4V at 107 was 185 ± 9 MPa for the as-built DMLS specimen, 169 ± 14 MPa for the as-built EBM specimen, 425 ± 9 MPa for the DMLS specimen treated using CASF & cavitation peening, and 386 ± 9 MPa for the EBM specimen treated using CASF & cavitation peening.

  35. Luminescence intensity of vortex cavitation in a Venturi tube changing with cavitation number International-journal Peer-reviewed

    Hitoshi Soyama

    Ultrasonics Sonochemistry　71　105389-105389　2021/03

    Publisher: Elsevier BV

    DOI： 10.1016/j.ultsonch.2020.105389 　

    ISSN： 1350-4177

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    Hydrodynamic cavitation in a Venturi tube produces luminescence, and the luminescence intensity reaches a maximum at a certain cavitation number, which is defined by upstream pressure, downstream pressure, and vapor pressure. The luminescence intensity of hydrodynamic cavitation can be enhanced by optimizing the downstream pressure at a constant upstream pressure condition. However, the reason why the luminescence intensity increases and then decreases with an increase in the downstream pressure remains unclear. In the present study, to clarify the mechanism of the change in the luminescence intensity with cavitation number, the luminescence produced by the hydrodynamic cavitation in a Venturi tube was measured, and the hydrodynamic cavitation was precisely observed using high-speed photography. The sound velocity in the cavitating flow field, which affects the aggressive intensity of the cavitation, was evaluated. The collapse of vortex cavitation was found to be closely related to the luminescence intensity of the hydrodynamic cavitation. A method to estimate the luminescence intensity of the hydrodynamic cavitation considering the sound velocity was developed, and it was demonstrated that the estimated luminescence intensity agrees well with the measured luminescence intensity.

  36. Enhancing the Aggressive Intensity of a Cavitating Jet by Introducing Water Flow Holes and a Long Guide Pipe Peer-reviewed

    Hirokazu Kamisaka, Hitoshi Soyama

    Journal of Fluids Engineering　143　(3)　2021/03/01

    Publisher: ASME International

    DOI： 10.1115/1.4048683 　

    ISSN： 0098-2202

    eISSN： 1528-901X

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    <title>Abstract</title> It is known that the geometry of the nozzle has a great effect on the aggressive intensity of a cavitating jet. In previous reports, various nozzle geometries were proposed, and improvements made to the aggressive intensity were reported. However, no detailed description of the reasons why the aggressive intensity is improved by these various geometries was given. In this study, we conducted erosion tests on pure aluminum Japanese Industrial Standards JIS A1050P using 11 different nozzles with different geometries downstream from the throat outlet in order to understand the effects of the nozzle geometry on the aggressive intensity. In addition, in order to investigate the characteristics of the cavitating jet produced by each nozzle, measurements of the erosion areas, images of the cavitating jet using a high-speed video camera, and measurements of the impingement pressure of the cavitating jet were taken, and correlations between the parameters were obtained. It was found that the nozzle with the largest mass loss was a nozzle with water flow holes near to the throat outlet and a long guide pipe (LGP). The mass loss was 2.5 times that of the previously reported optimum geometry nozzle. Very high correlations were obtained between the mass loss, the inner diameter of the annular erosion area, the impingement pressure measured at the same standoff distance and the cavitation cloud lifetime. Based on these results and the images of the cavitating jets taken with the high-speed video camera, a new cavitating jet progression process is proposed.

  37. Effect of compressive residual stress introduced by cavitation peening and shot peening on the improvement of fatigue strength of stainless steel International-journal International-coauthorship Peer-reviewed

    Hitoshi Soyama, Christopher R. Chighizola, Michael R. Hill

    Journal of Materials Processing Technology　288　116877-116877　2021/02

    Publisher: Elsevier BV

    DOI： 10.1016/j.jmatprotec.2020.116877 　

    ISSN： 0924-0136

  38. Effect of Cavitation Peening on Fatigue Properties in Friction Stir Welded Aluminum Alloy AA5754 International-journal International-coauthorship Peer-reviewed

    Hitoshi Soyama, Michela Simoncini, Marcello Cabibbo

    Metals　11　(1)　59-59　2020/12/30

    Publisher: MDPI AG

    DOI： 10.3390/met11010059 　

    eISSN： 2075-4701

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    Friction stir welding (FSW) is an attractive solid-state joining technique for lightweight metals; however, fatigue properties of FSWed metals are lower than those of bulk metals. A novel mechanical surface treatment using cavitation impact, i.e., cavitation peening, can improve fatigue life and strength by introducing compressive residual stress into the FSWed part. To demonstrate the enhancement of fatigue properties of FSWed metal sheet by cavitation peening, aluminum alloy AA5754 sheet jointed by FSW was treated by cavitation peening using cavitating jet in air and water and tested by a plane bending fatigue test. The surface residual stress of the FSWed part was also evaluated by an X-ray diffraction method. It was concluded that the fatigue life and strength of FSWed specimen were improved by cavitation peening. Whereas the fatigue life at σa = 150 MPa of FSWed specimen was about 1/20 of the bulk sheet, cavitation peening was able to extend the fatigue life of the non-peened FSW specimen by 3.6 times by introducing compressive residual stress into the FSWed part. This is the first paper to demonstrate the improvement of fatigue properties of FSWed metallic sheet by cavitation peening.

  39. Cavitation erosion resistance of the titanium alloy Ti–6Al–4V manufactured through additive manufacturing with various peening methods Peer-reviewed

    Hirotoshi Sasaki, Fuimo Takeo, Hitoshi Soyama

    Wear　462-463　203518-203518　2020/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.wear.2020.203518 　

    ISSN： 0043-1648

  40. Cavitating Jet: A Review Invited Peer-reviewed

    Hitoshi Soyama

    Applied Sciences　10　(20)　7280-7280　2020/10/17

    Publisher: MDPI AG

    DOI： 10.3390/app10207280 　

    eISSN： 2076-3417

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    When a high-speed water jet is injected into water through a nozzle, cavitation is generated in the nozzle and/or shear layer around the jet. A jet with cavitation is called a “cavitating jet”. When the cavitating jet is injected into a surface, cavitation is collapsed, producing impacts. Although cavitation impacts are harmful to hydraulic machinery, impacts produced by cavitating jets are utilized for cleaning, drilling and cavitation peening, which is a mechanical surface treatment to improve the fatigue strength of metallic materials in the same way as shot peening. When a cavitating jet is optimized, the peening intensity of the cavitating jet is larger than that of water jet peening, in which water column impacts are used. In order to optimize the cavitating jet, an understanding of the instabilities of the cavitating jet is required. In the present review, the unsteady behavior of vortex cavitation is visualized, and key parameters such as injection pressure, cavitation number and sound velocity in cavitating flow field are discussed, then the estimation methods of the aggressive intensity of the jet are summarized.

  41. Experimental Study of the Influence of Test Chamber Dimensions on Aggressive Intensity of the Cavitating Jet Peer-reviewed

    Haixia Liu, Can Kang, Hitoshi Soyama

    Journal of Testing and Evaluation　48　(5)　1-14　2020/09

    DOI： 10.1520/JTE20180573 　

    ISSN： 0090-3973

  42. Cavitation peening using pulse laser and submerged water jet to improve fatigue strength of aluminum alloy International-journal

    Hitoshi Soyama

    Journal of Material Sciences & Manufacturing Research　VID　(103)　2020/08

    Publisher: Scientific Research and Community Ltd

  43. Influence of the Size of Cylindrical Geometry in the Nozzle Outlet on Aggressive Intensity of Cavitating Jet Peer-reviewed

    Hirokazu Kamisaka, Hitoshi Soyama

    Journal of Jet Flow Engineering　35　(2)　12-19　2020/06/16

  44. Effect of Water Depth on Aggressive Intensity of a Cavitating Jet Peer-reviewed

    Hirokazu Kamisaka, Hitoshi Soyama

    Journal of Jet Flow Engineering　35　(2)　4-11　2020/06/16

  45. Effect of Various Peening Methods on the Fatigue Properties of Titanium Alloy Ti6Al4V Manufactured by Direct Metal Laser Sintering and Electron Beam Melting International-journal Peer-reviewed

    Hitoshi Soyama, Fumio Takeo

    Materials　13　(2216)　1-26　2020/05/12

    Publisher: MDPI

    DOI： 10.3390/ma13102216 　

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    Titanium alloy Ti6Al4V manufactured by additive manufacturing (AM) is an attractive material, but the fatigue strength of AM Ti6Al4V is remarkably weak. Thus, post-processing is very important. Shot peening can improve the fatigue strength of metallic materials, and novel peening methods, such as cavitation peening and laser peening, have been developed. In the present paper, to demonstrate an improvement of the fatigue strength of AM Ti6Al4V, Ti6Al4V manufactured by direct metal laser sintering (DMLS) and electron beam melting (EBM) was treated by cavitation peening, laser peening, and shot peening, then tested by a plane bending fatigue test. To clarify the mechanism of the improvement of the fatigue strength of AM Ti6Al4V, the surface roughness, residual stress, and surface hardness were measured, and the surfaces with and without peening were also observed using a scanning electron microscope. It was revealed that the fatigue strength at N = 107 of Ti6Al4V manufactured by DMLS was slightly better than that of Ti6Al4V manufactured by EBM, and the fatigue strength of both the DMLS and EBM specimens was improved by about two times through cavitation peening, compared with the as-built ones. An experimental formula to estimate fatigue strength from the mechanical properties of a surface was proposed.

  46. Cavitation Peening: A Review Peer-reviewed

    Hitoshi Soyama

    Metals　10　(2)　270-1-27　2020/02

    DOI： 10.3390/met10020270 　

  47. Effect of Bubble Radius on Ability of Submerged Laser Peening Peer-reviewed

    Hirotoshi Sasaki, Yuka Iga, Hitoshi Soyama

    Lecture Notes in Mechanical Engineering　283-291　2020

    Publisher: Springer Singapore

    DOI： 10.1007/978-981-15-0054-1_29 　

    ISSN： 2195-4356

    eISSN： 2195-4364

  48. Comparison between Shot Peening, Cavitation Peening, and Laser Peening by Observation of Crack Initiation and Crack Growth in Stainless Steel International-journal Peer-reviewed

    Hitoshi Soyama

    Metals　10　(1)　63-1-16　2019/12

    DOI： 10.3390/met10010063 　

  49. Use of an abrasive water cavitating jet and peening process to improve the fatigue strength of titanium alloy 6Al-4V manufactured by the electron beam powder bed melting (EBPB) additive manufacturing method Peer-reviewed

    Hitoshi Soyama, Daniel G. Sanders

    JOM　71　(12)　4311-4318　2019/12

    DOI： 10.1007/s11837-019-03673-8 　

  50. Improvement of Fatigue Strength of Additive Manufactured Metals by Solid-Liquid-Gas Interfacial Phenomena Induced by Pulse Laser Invited Peer-reviewed

    Hitoshi Soyama

    IOP Conf. Series: Materials Science and Engineering　611　012002-1-10　2019/11

  51. Enhancement of an aggressive intensity of a cavitating jet by water flow holes near nozzle outlet Peer-reviewed

    Hirokazu Kamisaka, Hitoshi Soyama

    Transactions of the JSME　85　(879)　19-00280-1-12　2019/11

    DOI： 10.1299/transjsme.19-00280 　

  52. Effect of Mechanical Properties on Fatigue Life Enhancement of Additive Manufactured Titanium Alloy Treated by Various Peening Methods Peer-reviewed

    Yuya Okura, Hirotoshi Sasaki, Hitoshi Soyama

    Proceedings of the 1st International Conference on Advanced Surface Enhancement (INCASE 2019)　88-96　2019/11

    DOI： 10.1007/978-981-15-0054-1_10 　

    ISSN： 2195-4356

    eISSN： 2195-4364

  53. Mechanical Surface Treatments of AISI 304 Stainless Steel: Effects on Surface Microrelief, Residual Stress, and Microstructure Peer-reviewed

    D.A. Lesyk, H. Soyama, B.N. Mordyuk, V.V. Dzhemelinskyi, S. Martinez, N.I. Khripta, A. Lamikiz

    Journal of Materials Engineering and Performance　28　(9)　5307-5322　2019/09

    DOI： 10.1007/s11665-019-04273-y 　

  54. Fundamentals and Applications of Cavitation Peening Comparing with Shot Peening and Laser Peening Peer-reviewed

    Hitoshi Soyama

    Proceedings of the 1st International Conference on Advanced Surface Enhancement (INCASE 2019)　76-87　2019/09

    DOI： 10.1007/978-981-15-0054-1_9 　

    ISSN： 2195-4356

  55. Comparison between the improvements made to the fatigue strength of stainless steel by cavitation peening, water jet peening, shot peening and laser peening Peer-reviewed

    Hitoshi Soyama

    Journal of Materials Processing Technology　269　65-78　2019/07

    DOI： 10.1016/j.jmatprotec.2019.01.030 　

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    In order to make a clear comparison between the various peening methods used to improve the fatigue strength<br /> of stainless steel 316L, the fatigue strength of specimens treated by cavitation peening, water jet peening, laser<br /> peening and shot peening were examined using a plate bending fatigue test. Both cavitation peening and water<br /> jet peening were carried out using a submerged water jet system, and these are distinguished by the distance<br /> from the nozzle to the specimen. A submerged laser peening system was used for laser peening. The impact with<br /> the surface due to laser cavitation was greater than that due to laser ablation. For each peening method, the<br /> optimum coverage was examined by measuring the fatigue life at constant bending stress. Then, the fatigue<br /> strength of specimens treated with the optimum coverage was examined. The fatigue strength of the non-peened<br /> specimen was 279 MPa, whereas it was 348 MPa for cavitation peening, 325 MPa for shot peening, 303 MPa for<br /> laser peening and 296 MPa for water jet peening. The fatigue strength of each peening method was affected by<br /> the surface roughness and work hardening.

  56. Cavitation Shotless Peening Effects on Fatigue Crack Growth Behaviour under Bending Loads Peer-reviewed

    Ali Al‐Turaihi, Ali Mehmanparast, Feargal Brennan, Hitoshi Soyama

    Material Design & Processing Communications　1　2019/06

    DOI： 10.1002/mdp2.88 　

    ISSN： 2577-6576

  57. Electricity Generation from Rice Bran by a Microbial Fuel Cell and the Influence of Hydrodynamic Cavitation Pretreatment Peer-reviewed

    Yuta Yoshimura, Kazunori Nakashima, Masaji Kato, Kengo Inoue, Fumiyoshi Okazaki, Hitoshi Soyama, Satoru Kawasaki

    ACS Omega　3　(11)　15267-15271　2018/11

    DOI： 10.1021/acsomega.8b02077 　

    ISSN： 2470-1343

  58. The Use of Various Peening Methods to Improve the Fatigue Strength of Titanium Alloy Ti6Al4V Manufactured by Electron Beam Melting Peer-reviewed

    SOYAMA Hitoshi, OKURA Yuya

    AIMS Materials Science　5　(5)　1000-1015　2018/10

    DOI： 10.3934/matersci.2018.5.1000 　

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    Additive manufacturing (AM) of metals is one of the foremost methods used for making medical implants and components for aviation. However, the fatigue strength of AM metals is weaker than that of the bulk equivalent. Mechanically treating the surface, such as by shot peening, can improve the fatigue strength, and novel peening methods without shot have also been proposed. In this paper, in order to demonstrate the improvements made in AM metals by various peening methods, specimens made of titanium alloy Ti6Al4V manufactured by electron beam melting (EBM) were treated by shot peening, laser peening and cavitation peening, then assessed by a plate bending fatigue test. In the case of shot peening, the shots were accelerated by a water jet to mitigate the incidence of dust during the process. For laser peening, the specimen was placed in water, and the effect of the impact produced at the target due to collapsing bubbles, which developed after laser ablation of the surface, was greater than the effect due to the laser ablation itself. For cavitation peening, the cavitation was generated by injecting a high speed water jet into water. In each case improvements in the fatigue strength of the Ti6Al4V were made. Improvements of 104% by laser peening, 84% by cavitation peening and 68% by shot peening compared with a non-peened specimen were achieved.

  59. Periodical Shedding of Cavitation Cloud Induced by a Cavitating Jet Peer-reviewed

    Hirokazu KAMISAKA, Hitoshi SOYAMA

    Proceedings of 23rd International Conference on Water Jetting　111-123　2018/09

  60. Suppression of Fatigue Crack Propagation of Duralumin by Hybrid Peening Peer-reviewed

    KOKUBUN Tomoyuki, SOYAMA Hitoshi

    Transactions of the JSME　84　1-14　2018/07

    DOI： 10.1299/transjsme.18-00161 　

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    Peening is one of the mechanical surface modification techniques, which is used to improve the fatigue strength by the introduction of the compressive residual stress into the surface of specimen. Several peening techniques, such as shot peening, cavitation peening and laser peening have been proposed and demonstrated the improvement of fatigue strength. Mechanical properties on surface modification layer vary with the techniques because of the difference of mechanism of impacts and strain rate. Therefore, it is possible to improve the fatigue strength further by hybrid peening, which is a combination of different peening techniques, due to controlling the mechanical properties on surface modification layer. In this paper, in order to demonstrate the suppression of fatigue crack propagation by hybrid peening combining shot peening and cavitation peening or cavitation peening and laser peening, the fatigue crack propagation in duralumin treated by hybrid peening was investigated, and the crack propagation behavior of the specimen treated by hybrid peening and single peening method was compared. The relationship between the fatigue crack propagation and the mechanical properties was also evaluated. It was revealed that hybrid peening (former process: laser peening, latter process: cavitation peening and former process: cavitation peening, latter process: shot peening) was more effective to suppress the fatigue crack propagation than single peening method and the number of cycle to failure of the specimen treated by hybrid peening was the largest. The new indicator f(R’, HV’, Rz’, ’) = R･HV･/Rz combined with four factors i.e. compressive residual stress R, Vickers hardness HV, full-width at half maximum  and maximum height roughness Rz showed the effect of suppression of fatigue crack propagation by peening.

  61. Surface Mechanics Design by Cavitation Peening Using Submerged Pulse Laser Peer-reviewed

    Hitoshi SOYAMA

    International Conference on Laser Peening and Related Phenomena　57-57　2018/05

  62. Interlaboratory Study on Standard Test Method for Erosion of Solid Materials by a Cavitating Jet Peer-reviewed

    Hitoshi Soyama, Seiji Shimizu, Shuji Hattori, Georges Chahine

    Proceedings of 10th International Symposium on Cavitation　1-4　2018/05

  63. Improvement of Wear Resistance of Steel by Means of a Cavitating Jet and a Submerged Pulse Laser Peer-reviewed

    SOYAMA Hitoshi, SATO Mitsuru

    Proceedings of 10th International Symposium on Cavitation　1-4　2018/05

  64. Effect of injection pressure on mechanical surface treatment using a submerged water jet Peer-reviewed

    Hirokazu KAMISAKA, Hitoshi SOYAMA

    Journal of Jet Flow Engineering　33　(2)　4-10　2018/03

  65. Estimation of aggressive intensity of a cavitating jet with multiple experimental methods Peer-reviewed

    Can Kang, Haixia Liu, Hitoshi Soyama

    Wear　394-395　176-186　2018/01/15

    Publisher: Elsevier Ltd

    DOI： 10.1016/j.wear.2017.11.001 　

    ISSN： 0043-1648

  66. Optimization of a cavitating jet for removing dental plaque from the surface of the screw of an implant and its practical application Peer-reviewed

    Junki Yamada, Kewen Peng, Tomoyuki Kokubun, Takashi Takiguchi, Gensheng Li, Matsuo Yamamoto, Hitoshi Soyama

    Journal of Biomechanical Science and Engineering　13　(2)　1-12　2018

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/jbse.17-00102 　

    ISSN： 1880-9863

  67. Removal of Oral Biofilm on an Implant Fixture by a Cavitating Jet Peer-reviewed

    Junki Yamada, Takashi Takiguchi, Akihiro Saito, Hibiki Odanaka, Hitoshi Soyama, Matsuo Yamamoto

    IMPLANT DENTISTRY　26　(6)　904-910　2017/12

    DOI： 10.1097/ID.0000000000000681 　

    ISSN： 1056-6163

  68. Key Factors and Applications of Cavitation Peening Invited Peer-reviewed

    Hitoshi Soyama

    International Journal of Peening Science and Technology　1　(1)　3-60　2017/12

    ISSN： 2473-506X

  69. Evaluation of the effect of pressure conditions on the aggressive intensity of hydrodynamic cavitation produced by a Venturi tube Peer-reviewed

    星野 柊, 祖山 均

    日本機械学会論文集　83　(855)　1-12　2017/11/25

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.17-00400 　

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    <p>For hydrodynamic cavitation produced by a Venturi tube, cavitation bubble is collapsed at downstream of a nozzle and its intensity is influenced by upstream pressure and downstream pressure. In order to investigate the effect of the upstream pressure p1 and the downstream pressure p2 on aggressive intensity of hydrodynamic cavitation, an experiment measuring acoustic power by an AE sensor was conducted. Relationship between pressure conditions and acoustic power PA was studied. The higher the upstream pressure p1, the higher the acoustic power PA. Acoustic power had a maximum value at the upstream pressure p1 = 1.6, 2.1, 2.6, 3.1 and 3.6 MPa. At the upstream pressure p1 = 2.6 MPa and the downstream pressure p2 = 0.5 MPa, the aggressive intensity of hydrodynamic cavitation increased to be 36 times larger of the value corresponding to the atmospheric downstream pressure. While the optimum downstream pressure depended on the upstream pressure, the cavitation number was nearly constant for all upstream pressures. It was concluded that increasing the downstream pressure is an effective means to increase the aggressive intensity of the hydrodynamic cavitation without increasing the input energy.</p>

  70. Introduction of Compressive Residual Stress into Alloy Tool Steel by Submerged Laser Peening Utilizing Laser Cavitation Impact Peer-reviewed

    Hitoshi Soyama

    Proceedings of 9th International Conference on Leading Edge Manufacturing in 21st Century (LEM21)　2017/11/14

  71. Effect of Heat Treatment on the Cavitation Erosion Resistance of Stainless Steel Peer-reviewed

    Kewen Peng, Can Kang, Gensheng Li, Kyuhei Matsuda, Hitoshi Soyama

    Materials and Corrosion　10.1002/maco.201709818　1-9　2017/11/10

    DOI： 10.1002/maco.201709818/full 　

  72. Improvement of Tensile Fatigue Strength of Duralumin Plate with a Hole by Cavitation Peening Using Opposed Cavitating Jets Peer-reviewed

    Hitoshi Soyama, Fumio Takeo

    Proceedings of 13th International Conference on Shot Peening　398-401　2017/09/19

  73. Introduction of Compressive Residual Stress into Alloy Steel by Cavitation Peening Using Laser Cavitation Peer-reviewed

    Hitoshi Soyama

    Proceedings of 13th International Conference on Shot Peening　414-417　2017/09/19

  74. Surface Strengthening of AISI4140 by Cavitation Peening Peer-reviewed

    Alexander Klumpp, Franziska Lienert, Stefan Dietrich, Hitoshi Soyama, Volker Schulze

    Proceedings of 13th International Conference on Shot Peening　441-446　2017/09/19

  75. 水中レーザピーニングによる合金工具鋼への圧縮残留応力導入とX線回折を用いた評価 Peer-reviewed

    祖山 均, 佐藤 充

    ショットピーニング技術　29　(3)　132-138　2017/09

  76. Evaluation of fatigue crack propagation in surface modification layer of duralumin treated by various peening Peer-reviewed

    Tomoyuki KOKUBUN, Hitoshi SOYAMA

    Transactions of the JSME　83　(853)　No.17-00190-1-15　2017/08

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.17-00190 　

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    <p>Peening techniques are used to introduce the compressive residual stress into the surface of metallic materials in order to improve the fatigue properties. The fatigue crack propagation is affected by many factors in surface modification layer, however, the effect of these factors on the fatigue crack propagation is not clarified in detail. In this study, the fatigue crack propagation behavior in surface modification layer of duralumin treated by various peening techniques including shot peening, cavitation peening and laser peening was investigated. The relationship between the fatigue crack propagation behavior and mechanical properties was also evaluated. The fatigue crack propagation behavior varies depending on peening techniques despite the condition of the same peening intensity, since the mechanical properties in surface modification layer are changed with the peening techniques. The compressive residual stress σR and Vickers hardness HV are the important factors about fatigue crack propagation, however they do not show a correlation with the number of cycle to failure of the specimen Nf. Therefore, the new indicator combined with four factors i.e. σR, HV, full-width at half maximum β and maximum height roughness Rz were proposed. It revealed a significant correlation with Nf, and possibility to evaluate the effect of suppression of fatigue crack propagation by peening.</p>

  77. Formation of CaCO3 film on metal surface by laser irradiation Peer-reviewed

    星野純輝, 祖山均

    日本機械学会論文集　83　(849)　1-11　2017/05/25

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.16-00502 　

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    <p>In order to establish a new approach to manufacturing of CaCO3 which can be adapted to structural materials, the formation of CaCO3 using continuous-wave laser has been conducted on austenitic stainless steel JIS SUS316L surface. It has been demonstrated that localized heating by laser irradiation could control the formation. CaCO3 was obtained from heating Ca(HCO3)2. The film thickness of CaCO3 formed at various conditions was measured, therefore it was revealed the effect of various factors on the formation of CaCO3. The higher laser power P, the thicker the film thickness of CaCO3, however, high laser power (1.5 W) decreases the film thickness when laser irradiation is continued for many hours. Changing the distance from condenser lens d to specimen, it can control the film thickness and the width of CaCO3 film without <del>input of</del> increasing energy. When the velocity of specimen v is 1.0 mm/s, the film thickness is the highest among other velocities and the shape of CaCO3 film is clear. The temperature of Ca(HCO3)2 Tw have not much effect on the film thickness, although the temperature have effect on the width of CaCO3 film. Therefore, CaCO3 film can be formed efficiently by controlling the factors such as laser power. The optimum condition of fabrication of CaCO3 which we inferred from these results was P = 1.0 W, d = 30 mm, v = 0.1 mm/s, Tw = 45 °C, laser irradiation time t = 5 h. This manufacturing have probability to be able to fabricate the structure of CaCO3 flexibly.</p>

  78. 水中高速水噴流を用いたステンレス鋼の機械的表面改質におけるキャビテーションピーニングとウォータショットピーニングとの相違 Peer-reviewed

    上坂洋雄, 徳道世一, 祖山均

    ショットピーニング技術　29　(2)　76-82　2017/05/25

  79. Improvement of fatigue strength of welded part in stainless steel by peening method using a water jet Peer-reviewed

    高桑脩, 祖山均

    噴流工学　33　(1)　4-9　2017/02/28

    Publisher:

    ISSN： 1341-3279

  80. Effect of Impact at Bubble Collapse of Submerged Laser Peening and Its Application for Introduction of Compressive Residual Stress into Tool Alloy Steel Peer-reviewed

    Tomoyuki Kokubun, Hitoshi Soyama

    Journal of Shot Peening Technology of Japan　29　(1)　1-7　2017/01

  81. Using cavitation peening to enhance the fatigue strength of duralumin plate containing a hole with rounded edges Peer-reviewed

    O. Takakuwa, F. Takeo, M. Sato, H. Soyama

    SURFACE & COATINGS TECHNOLOGY　307　200-205　2016/12

    DOI： 10.1016/j.surfcoat.2016.08.087 　

    ISSN： 0257-8972

  82. Opposed Cavitating Jets and their Application for Cavitation Peening of Wall Surrounding Hole Peer-reviewed

    Hitoshi Soyama

    Proceedings of 23rd International Conference on Water Jetting　201-208　2016/11/14

  83. Digging of Concrete by a Cavitating Jet in Air Comparing with a Conventional Water Jet Peer-reviewed

    Hitoshi Soyama, Kyuhei Matsuda, Mitsuhiro Mikami

    Proceedings of 23rd International Conference on Water Jetting　209-214　2016/11/14

  84. Preventing Hydrogen Diffusion in Stainless Steel by Cavitating Jet in Air Peer-reviewed

    Osamu Takakuwa, Hitoshi Soyama

    Proceedings of 23rd International Conference on Water Jetting　215-221　2016/11/14

  85. Enhancing the durability of spinal implant fixture applications made of Ti-6Al-4V ELI by means of cavitation peening Peer-reviewed

    Osamu Takakuwa, Masaaki Nakai, Kengo Narita, Mitsuo Niinomi, Kazuhiro Hasegawa, Hitoshi Soyama

    INTERNATIONAL JOURNAL OF FATIGUE　92　(1)　360-367　2016/11

    DOI： 10.1016/j.ijfatigue.2016.07.021 　

    ISSN： 0142-1123

    eISSN： 1879-3452

  86. 岩石のメカノルミネッセンスによる発光における支配因子の検討 Peer-reviewed

    髙桑 脩, 宮坂 晃輔, 祖山 均

    日本機械学会論文集　82　(842)　16-00169-1-12　2016/09/30

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.16-00169 　

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    <p>The objective of the present study is to investigate a factor on luminescence of rock induced by mechanical action such as fracture and/or sliding. The luminescence was caused by 3-points destructive test and sliding slip test. It was observed by an electron multiplication cooled charged-coupled device camera, i.e., EM-CCD camera. The intensity of the luminescence was also detected by a luminescence analyzer employing a photomultiplier tube. In order to reveal the role of SiO2 as a factor of piezoelectric effect, tensile strength and ambient gas plasma, SiO2 amount was measured using X-ray diffraction analysis. The test was carried out in air, nitrogen or oxygen. In addition, a spectrum analysis was done during slide slip test to verify the role of ambient gas on the luminescence. From the obtained results, it was revealed that the luminescence appears by fracture loaded by the 3-points bending and also the sliding slip test. The spot-like luminescence can be observed by the EM-CCD camera. The luminescence intensity depends on SiO2 amount in rocks and its tensile strength. When nitrogen is used as ambient gas, the luminescence becomes stronger. The luminescence of rock can be generated by plasma of ambient gas induced by piezoelectric effect in mechanical action, i.e., fracture and/or sliding.</p>

  87. キャビテーションピーニングによるクロムモリブデン鋼製ボルトの遅れ破壊耐性の向上 Peer-reviewed

    熊谷 直輝, 髙桑 脩, 祖山 均

    日本機械学会論文集　82　(842)　16-00111-1-13　2016/09/16

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.16-00111 　

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    <p>In order to demonstrate the effect of cavitation peening on crack initiation stage of hydrogen-charged materials with the objective of industrial application, and suppression of the delayed fracture of bolt, the delayed fracture test was conducted under constant load after hydrogen charging. The obtained results show that fracture surface at an origination of the delayed fracture took on intergranular fracture, and fracture occurred in a moment after crack initiate from stress concentration portion such as root of thread potion and incomplete thread. That is to say, evaluation of crack initiation stage of hydrogen-charged materials can be achieved by the delayed fracture test. Threshold stress σth of the delayed fracture was increased by cavitation peening and kept on increasing with processing time of cavitation peening. σth increased from 327 ± 22 MPa to 505 ± 42 MPa due to cavitation peening with tp = 6 s/mm. This effect was caused by introduction of compressive residual stress at root of thread potion, where subject to be fracture origin.</p>

  88. Effect of Nozzle Throat Length on Aggressive Intensity of a Cavitating Jet Peer-reviewed

    熊谷 直輝, 祖山 均

    Jet Flow Engineering　32　(2)　25-32　2016/05/24

    Publisher:

    ISSN： 1341-3279

  89. Using Cavitation Peening to Improve the Fatigue Life of Titanium Alloy Ti-6Al-4V Manufactured by Electron Beam Melting Peer-reviewed

    Mitsuru Sato, Osamu Takakuwa, Masaaki Nakai, Mitsuo Niinomi, Fumio Takeo, Hitoshi Soyama

    Materials Science and Applications　7　(4)　181-191　2016/04/20

    DOI： 10.4236/msa.2016.74018 　

  90. Enhancing the aggressive intensity of hydrodynamic cavitation through a Venturi tube by increasing the pressure in the region where the bubbles collapse Peer-reviewed

    H. Soyama, J. Hoshino

    AIP ADVANCES　6　(4)　045113-1-045113-13　2016/04

    DOI： 10.1063/1.4947572 　

    ISSN： 2158-3226

  91. Increase in Threshold Stress Intensity Factor Range by Re-circulating Shot Peening Method Using a Water Jet Peer-reviewed

    Akima NAITO, Osamu TAKAKUWA, Hitoshi SOYAMA

    Jet Flow Engineering　32　(1)　4-9　2016/03/31

    Publisher:

    ISSN： 1341-3279

  92. Hydrodynamic Cavitation Reactor for Efficient Pretreatment of Lignocellulosic Biomass Peer-reviewed

    Kazunori Nakashima, Yuuki Ebi, Naomi Shibasaki-Kitakawa, Hitoshi Soyama, Toshikuni Yonemoto

    INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH　55　(7)　1866-1871　2016/02

    DOI： 10.1021/acs.iecr.5b04375 　

    ISSN： 0888-5885

  93. Comparison between cavitation peening and shot peening for extending the fatigue life of a duralumin plate with a hole Peer-reviewed

    Hitoshi Soyama, Fumio Takeo

    JOURNAL OF MATERIALS PROCESSING TECHNOLOGY　227　80-87　2016/01

    DOI： 10.1016/j.jmatprotec.2015.08.012 　

    ISSN： 0924-0136

  94. Suppression of Fatigue Crack Propagation of Duralumin by Cavitation Peening Peer-reviewed

    Hitoshi Soyama, Naoki Kumagai, Osamu Takakuwa, Fumio Takeo

    Journal of Engineering　1-3　2015/08/04

    DOI： 10.1049/joe.2015.0066 　

  95. Preventing Hydrogen Embrittlement in Stainless Steel by Means of Compressive Stress Induced by Cavitation Peening Peer-reviewed

    Osamu Takakuwa, Hitoshi Soyama

    Journal of Engineering　1-4　2015/07/29

    DOI： 10.1049/joe.2015.0065 　

  96. Surface Mechanics Design by Cavitation Peening Peer-reviewed

    Hitoshi Soyama

    Journal of Engineering　1-5　2015/07/28

    DOI： 10.1049/joe.2015.0055 　

  97. 水中ウォータージェットによる機械的表面改質におけるキャビテーションピーニングとウォータージェットピーニングの判別法 Peer-reviewed

    祖山均

    噴流工学　31　(2)　12-19　2015/05/25

    Publisher:

    ISSN： 1341-3279

  98. ヘマタイトの熱電変換特性に及ぼす陽極酸化条件の影響 Peer-reviewed

    十二町直哉, 祖山均

    日本機械学会論文集　81　(825)　14-00549-1-9　2015/05/25

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.14-00549 　

    ISSN： 2187-9761

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    The purpose of this study is to investigate the effect of fabrication conditions for α-Fe2O3 basedthermoelectric conversion elements. It was demonstrated that the open circuit voltage of α-Fe2O3 thermoelectric conversion elements could be enhanced by decreasing the load current density used in production of the film by anodic oxidation. α-Fe2O3 films were fabricated under various oxidizing condition in an aqueous solution of FeCl3, KF, KCl and H2O2 at the temperature of 50 °C. The load current density and oxidation time were varied. The amount of α-Fe2O3 in the α-Fe2O3 film, the crystal quality and the crystal grain size of the α-Fe2O3, were evaluated. In terms of the maximum value of the open circuit voltage, the best film thickness of the α-Fe2O3 film was found to be about 40 ~ 50 μm. α-Fe2O3 films with greater crystal quality and larger crystal grain size can be fabricated by decreasing the load current density. These improvement on α-Fe2O3 thermoelectric conversion elements lead to more powerful thermoelectric conversion element, i.e., higher open circuit voltage.

  99. キャビテーションピーニングによるオーステナイト系ステンレス鋼への水素侵入抑止 Peer-reviewed

    髙桑脩, 眞野優太, 祖山均

    日本機械学会論文集　81　(824)　14-00638-1-13　2015/04/25

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.14-00638 　

    ISSN： 2187-9761

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    It has been demonstrated in the present paper that compressive residual stress introduced by cavitation peening can prevent hydrogen invasion into surface of austenitic stainless steel JIS SUS316L. The specimen was treated by cavitation peening employing a cavitating jet in air. After that, the residual stress measurement was performed using an X-ray diffraction analysis with 2D method. Then the surface was catholically charged with hydrogen. Hydrogen content was evaluated by a thermal desorption analysis using a gas chromatography. The obtained results show the compressive residual stress reduces hydrogen content by 85 % when the compressive residual stress is 378 MPa. The hydrogen content decreases along with increase in the compressive residual stress. Considering a profile of the compressive residual stress with respect to depth from the surface, suppressive effect on hydrogen invasion and area of compressive residual stress in depth direction has a strong correlation whose correlation coefficient is 0.997 and the probability of uncorrected is less than 0.1 %.

  100. 微小圧子押込み試験によるオーステナイト系ステンレス鋼の水素侵入評価 Peer-reviewed

    眞野優太, 髙桑脩, 祖山均

    日本機械学会論文集　81　(823)　14-00426-1-15　2015/03/25

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.14-00426 　

    ISSN： 2187-9761

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    In order to investigate the relationship between hydrogen-induced hardening of austenitic stainless steel and the hydrogen content, the spherical micro-indentation tests and thermal desorption analysis have been conducted on hydrogen charged austenitic stainless steel JIS SUS316L. Due to the relatively low hydrogen embrittlement susceptibility, this material has been widely used in a hydrogen environment. Hydrogen has been charged by using a cathodic method. In order to change the hydrogen content, charging current density and charging time were changed from 0.01 to 1.0 mA/mm2, from 0 to 48 h, respectively. The obtained results show the hardness increases along with charging current density and charging time. The maximum change in the hardness is 28 %. Hydrogen content also depends on the charging current density and charging time. These relationships result in the strong linear correlation between hydrogen-induced hardening rate and the hydrogen content. Their correlation factor is 0.98 and the probability that these are uncorrelated is less than 0.001 %. The depth of hydrogen absorption was investigated by using secondary ion mass spectroscopy (SIMS). Hydrogen-induced hardening might be due to dislocation-pinning effect of hydrogen during indentation process. This phenomenon is dependent on not so much hydrogen absorption depth as hydrogen content. By using this phenomenon, there is a possibility to apply micro-indentation tests for evaluation of local hydrogen content.

  101. Movement of Dislocations in the Sub-Surface of a Polycrystalline Metal by Cavitation Peening Observed by Transmission Electron Microscopy Peer-reviewed

    Takakuwa, Akihiko Chiba, Hitoshi Soyama

    Materials Sciences and Applications　6　(2)　140-144　2015/01/30

    DOI： 10.4236/msa.2015.62017 　

  102. Effect of Residual Stress on the Corrosion Behavior of Austenitic Stainless Steel Peer-reviewed

    Osamu Takakuwa, Hitoshi Soyama

    Advances in Chemical Engineering and Science　5　(1)　62-71　2015/01/15

    DOI： 10.4236/aces.2015.51007 　

  103. Mechanical Surface Treatment of Duralumin Plate by Bubble Induced by Pulse Laser Peer-reviewed

    H. Soyama, H. Sasaki, S. Endo, Y. Iga

    9TH INTERNATIONAL SYMPOSIUM ON CAVITATION (CAV2015)　656　(012108)　1-4　2015

    DOI： 10.1088/1742-6596/656/1/012108 　

    ISSN： 1742-6588

  104. Surface Mechanics Design of Metallic Materials on Mechanical Surface Treatments Invited Peer-reviewed

    Hitoshi Soyama

    Mechanical Engineering Reviews　2　(1)　Paper No. 14-00192-1-20　2015/01

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/mer.14-00192 　

    ISSN： 2187-9753

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    In order to control the surface mechanics of a metallic material, mechanical treatment of the surface, such as by shot peening, water jet peening, cavitation peening or laser peening, is often done. In this review paper, we discuss the mechanical properties of such treated surfaces and the effect of the treatment on fatigue strength. Although there is a detrimental increase in surface roughness introduced by the various treatments, the positive effects, such as the introduction of compressive residual stress and/or work hardening, i.e., an increase in the yield stress, outweigh the negative effects, then treatments improve the fatigue strength. The compressive residual stress introduced by the various treatments is closely related to the crack closure and crack initiation. If the same peening process is used, the fatigue strength can be estimated from the residual stress distribution. However, when the mechanical surface treatments were different, the residual stress distribution of the specimen at the same fatigue strength was totally different. Namely, when different peening processes are applied to the surface, the compressive residual stress only shows a tendency to improve the fatigue strength, and the fatigue strength cannot be evaluated precisely from the residual stress distribution, Thus, a fatigue test is required to evaluate the fatigue strength. As the fatigue strength strongly depend on the crack initiation, an evaluation of the threshold level of the stress intensity factor range of a treated surface is valuable, and it can be possible by a plate bending fatigue test using a notched specimen.

  105. Application of Re-circulating Shot Peening Method Using a Water Jet to Spinal Impant Rod Peer-reviewed

    Osamu Takakuwa, Hitoshi Soyama

    Journal of Jet Flow Engineering　31　(1)　20-27　2014/12/12

    Publisher:

    ISSN： 1341-3279

  106. Reduction of hydrogen embrittlement cracking of stainless steel SUS316L by cavitation peening Peer-reviewed

    H. Soyama, O. Takakuwa

    Recent Advances in Structural Integrity Analysis: Proceedings of the International Congress (APCF/SIF-2014)　401-405　2014/12/09

  107. The Interaction between Hydrogen and Surface Stress in Stainless Steel Peer-reviewed

    Osamu TAKAKUWA, Yuta MANO, Hitoshi SOYAMA

    Proceedings of the 12th International Conference on Material Science and Engineering Technology　1285-1289　2014/12

  108. Improvement of Threshold Stress Intensity Factor Range of Stainless Steel by Cavitation Peening Peer-reviewed

    Hitoshi Soyama

    Proceedings of 12th International Conference on Shot Peening　55-60　2014/09/15

  109. Improvement of Fatigue Strength of Duralumin Plate with a Hole by a Cavitating Jet Peer-reviewed

    Hitoshi Soyama

    Proceedings of 22nd International Conference on Water Jetting　57-65　2014/09/03

  110. The Use of Cavitation Peening to Increase the Fatigue Strength of Duralumin Plates Containing Fastener Holes Peer-reviewed

    Hitoshi Soyama

    Materials Sciences and Applications　5　(6)　430-440　2014/05/28

    DOI： 10.4236/msa.2014.56047 　

  111. Increase in the local yield stress near surface of austenitic stainless steel due to invasion by hydrogen Peer-reviewed

    O. Takakuwa, Y. Mano, H. Soyama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY　39　(11)　6095-6103　2014/04

    DOI： 10.1016/j.ijhydene.2014.01.190 　

    ISSN： 0360-3199

    eISSN： 1879-3487

  112. Evaluation of fatigue crack propagation in surface modification layer by a load-controlled plate bending fatigue tester Peer-reviewed

    Osamu TAKAKUWA, Kazumasa SANADA, Hitoshi SOYAMA

    Transactions of the JSME　80　(810)　smm0022-1-17　2014/02

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/transjsme.2014smm0022 　

    ISSN： 2187-9761

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    The objective of this study is to evaluate fatigue crack propagating behavior in surface modification layer treated by peening. A load-controlled plate bending fatigue tester has been developed in this study. This makes possible to evaluate relation between stress intensity factor range and fatigue crack growth rate, i.e., da/dN-ΔK diagram, in the surface modification layer, since the tester keeps the load constant differently from a displacement-controlled tester. Although the displacement-controlled fatigue tester which keeps displacement constant has been widely used to evaluate the fatigue crack propagating behavior, an applied load, i.e., stress ratio, changes along with crack propagating. In this study, the fatigue crack propagation test was conducted on specimens treated by cavitation peening, which is one of the surface modification techniques, and mechanical properties were also evaluated, including residual stress, yield stress and Vickers hardness, so as to reveal the effect of such mechanical properties varied by the peeing on the fatigue crack propagating behavior. It was concluded that the da/dN-ΔK diagram determined by the tester follows the Paris law and ΔK at da/dN = 10-9 ～ 10-8 was increased more than twice by cavitation peening. The increment has a relation with the mechanical properties varied by the peening.

  113. EFFECT OF INDENTATION LOAD ON VICKERS HARDNESS OF AUSTENITIC STAINLESS STEEL AFTER HYDROGEN CHARGING Peer-reviewed

    Osamu Takakuwa, Yuta Mano, Hitoshi Soyama

    ASME PRESSURE VESSELS AND PIPING CONFERENCE - 2014, VOL 6B　2014

  114. Effect of load current density during the production of Cu2O/Cu solar cells by anodic oxidation on film quality and output power Peer-reviewed

    K. Hasuda, O. Takakuwa, H. Soyama

    SOLID-STATE ELECTRONICS　91　130-136　2014/01

    DOI： 10.1016/j.sse.2013.09.007 　

    ISSN： 0038-1101

    eISSN： 1879-2405

  115. キャビテーションピーニングで加工したクロムモリブデン鋼の渦電流法による非破壊評価 Peer-reviewed

    祖山 均, 熊谷 直輝

    ショットピーニング技術　26　(1)　8-15　2014/01

  116. Effect of hydrogen on the micro- and macro-strain near the surface of austenitic stainless steel Peer-reviewed

    Osamu Takakuwa, Yuta Mano, Hitoshi Soyama

    Advanced Materials Research　936　1298-1302　2014

    Publisher: Trans Tech Publications Ltd

    DOI： 10.4028/www.scientific.net/AMR.936.1298 　

    ISSN： 1662-8985 1022-6680

  117. Evaluation of the efficiency of cleaning dental plaque on titanium using a cavitating jet Peer-reviewed

    Mariko Kikuchi, Takashi Takiguchi, Junki Yamada, Matsuo Yamamoto, Hitoshi Soyama

    Journal of Biomechanical Science and Engineering　9　(3)　1-8　2014

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/jbse.14-00297 　

    ISSN： 1880-9863

  118. Enhancing the Aggressive Intensity of a Cavitating Jet by Introducing a Cavitator and a Guide Pipe Peer-reviewed

    Hitoshi SOYAMA

    Journal of Fluid Science and Technology　9　(1)　jfst0001-1-12　2014/01

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jfst.2014jfst0001 　

    ISSN： 1880-5558

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    In order to enhance the aggressive intensity of a cavitating jet for practical applications, such as cavitation peening, a nozzle equipped with an additional nozzle upstream from the main nozzle, i.e., a cavitator, and a guide pipe downstream from the main nozzle was proposed and optimized. The aggressive intensity of the jet was evaluated by the residual plastic deformation, i.e., the radius of curvature, in duralumin plate specimens subjected to the jet perpendicullary. The radius of curvature can be considered to be directly related to the aggressive intensity of the jet, as the plastic deformation such as introduction of compressive residual stress and/or work hardening in metallic materials is important parameters on cavitation peening. The deformation occurs because the pressure due to cavitation impacts is beyond the yield stress of the specimens. It was demonstrated that a nozzle equipped with an optimized cavitator and optimized guide pipe increased the aggressive intensity of the jet by a factor of 4.2 without an increase of the jet power, compared to the jet obtained with a conventional nozzle with neither cavitator nor guide pipe, as the cavitator fed cavitation nuclei for the jet and the guide pipe enlarged the cavitation clouds of the jet.

  119. Estimation of the Yield Stress of Stainless Steel from the Vickers Hardness Taking Account of the Residual Stress Peer-reviewed

    Osamu Takakuwa, Yusuke Kawaragi, Hitoshi Soyama

    Journal of Surface Engineered Materials and Advanced Technology　3　262-268　2013/10

    DOI： 10.4236/jsemat.2013.34035 　

  120. Comparison of mechanisms of advanced mechanical surface treatments in nickel-based superalloy Peer-reviewed

    Amrinder Gill, Abhishek Telang, S. R. Mannava, Dong Qian, Young-Shik Pyoun, Hitoshi Soyama, Vijay K. Vasudevan

    MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　576　346-355　2013/08

    DOI： 10.1016/j.msea.2013.04.021 　

    ISSN： 0921-5093

    eISSN： 1873-4936

  121. Introduction of Compressive Residual Stress by Means of Cavitation Peening into a Titanium Alloy Rod Used for Spinal Implants Peer-reviewed

    Osamu Takakuwa, Amrinder S. Gill, Gokul Ramakrishnan, Seetha R. Mannava, Vijay K. Vasudevan, Hitoshi Soyama

    Materials Sciences and Applications　4　(7A2)　23-28　2013/07/18

    DOI： 10.4236/msa.2013.47A2004 　

  122. An Indicator for the Suppression of Fatigue Crack Growth by Hybrid Peening Peer-reviewed

    Osamu TAKAKUWA, Kouhei YAMAMIYA, Hitoshi SOYAMA

    Journal of Solid Mechanics and Materials Engineering　7　(3)　357-371　2013/05/31

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jmmp.7.357 　

    ISSN： 1880-9871

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    Peening techniques are used to introduce compressive residual stress into the surface of a metal in order to improve the fatigue properties and resistance to stress corrosion cracking of the metal. The present paper focuses on the effect of peening on the fatigue crack growth behavior in austenitic stainless steel. An indicator which can be used to determine by how much the fatigue crack growth can be suppressed was found. Regardless of the type of peening technique used, a much closer correlation to the number of cycles to failure was found with the area of integration under the compressive residual stress curve with respect to depth than with the compressive residual stress at the surface. Moreover hybrid peening, which is a combination of different peening techniques, was developed in this study in order to enhance the favorable effects of peening. Hybrid peening increased the area of integration under the compressive residual stress curve and, as a result, a further increase in the number of cycles to failure compared to single peening was obtained.

  123. Optimizing the Conditions for Residual Stress Measurement Using a Two-Dimensional XRD Method with Specimen Oscillation Peer-reviewed

    Osamu Takakuwa, Hitoshi Soyama

    Advances in Materials Physics and Chemistry　3　8-18　2013/04/26

    DOI： 10.4236/ampc.2013.31A002 　

  124. Effect of Nozzle Outlet Geometry of a High-Speed Water Jet on Cutting Ability of Submerged Abrasive Water Jet Peer-reviewed

    Hitoshi Soyama

    Proceedings of 10th Pacific Rim International Conference on Water Jet Technology　237-242　2013/04/25

  125. Effect of nozzle geometry on a standard cavitation erosion test using a cavitating jet Peer-reviewed

    Hitoshi Soyama

    Wear　297　(1-2)　895-902　2013/01/15

    DOI： 10.1016/j.wear.2012.11.008 　

    ISSN： 0043-1648

  126. Improvement of mechanical properties of dental materials by shot peening Peer-reviewed

    Yoshiteru Aoyagi, Yusuke Kawaragi, Ai Tokue, Chikahiro Ohkubo, Osamu Takakuwa, Hitoshi Soyama

    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A　79　(803)　1019-1029　2013

    DOI： 10.1299/kikaia.79.1019 　

    ISSN： 0387-5008

  127. Analysis of the formation of plastic deformation layer on the surface of polycrystalline metals subjected to a micro-size high-rate shot impact Peer-reviewed

    Shinya Kanou, Masaaki Nishikawa, Hitoshi Soyama

    International Journal of Mechanical Sciences　75　316-323　2013

    DOI： 10.1016/j.ijmecsci.2013.07.014 　

    ISSN： 0020-7403

  128. Similarity Law on Shedding Frequency of Cavitation Cloud Induced by a Cavitating Jet Peer-reviewed

    Satoshi NISHIMURA, Osamu TAKAKUWA, Hitoshi SOYAMA

    Journal of Fluid Science and Technology　7　(3)　405-420　2012/12/20

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jfst.7.405 　

    ISSN： 1880-5558

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    In order to clarify the mechanism of cavitation cloud shedding, the shedding frequencies of cavitation clouds were investigated by high-speed observations and image analysis. The results indicate that the shedding frequency follows the similarity law for unsteady vortex flow. The ranges of parameters considered were from 0.4 to 2.0 mm for the nozzle throat diameter, from 10 to 30MPa for the injection pressure, and from 0.01 to 0.05 for the cavitation number. The similarity law is discussed with reference to the Strouhal number, which depends on the shedding frequency of the cavitation cloud, the width of the cavitating jet and the jet velocity at the nozzle exit. Formulas describing the relationships between the shedding frequency of the cavitation cloud and the investigated parameters were developed. In addition, the Strouhal number for cavitation cloud shedding was shown to be independent of the investigated parameters and constant, with a value of 0.18. In fact, the cavitation cloud shedding was governed by the constant Strouhal number.

  129. Effect of the impact energy of various peening techniques on the induced plastic deformation region Peer-reviewed

    S. Kanou, O. Takakuwa, S. R. Mannava, D. Qian, V. K. Vasudevan, H. Soyama

    JOURNAL OF MATERIALS PROCESSING TECHNOLOGY　212　(10)　1998-2006　2012/10

    DOI： 10.1016/j.jmatprotec.2012.05.003 　

    ISSN： 0924-0136

  130. Effect of Nozzle Shape for High Injection Pressure on Aggressivity of Cavitating Jet Peer-reviewed

    H. Soyama, O. Takakuwa, A. Naito

    Proceedings of 21st International Conference on Water Jetting　367-378　2012/09/19

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    ISBN : 978 1 85598 131 7

  131. Power Law of Injection Pressure and Nozzle Diameter on Aggressive Intensity of a Cavitating Jet Peer-reviewed

    H. Soyama

    Proceedings of 21st International Conference on Water Jetting　343-354　2012/09/19

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    ISBN : 978 1 85598 131 7

  132. Effect of Dissolve Gas on Luminescent Spots Induced by a Cavitating Jet Peer-reviewed

    Hitoshi Soyama

    Proceedings of 8th International Symposium on Cavitation　788-793　2012/08/13

    DOI： 10.3850/978-981-07-2826-7_101 　

  133. Estimation of the depth of surface modification layer induced by cavitation peening Peer-reviewed

    O. Takakuwa, M. Nishikawa, H. Soyama

    JOURNAL OF MATERIALS PROCESSING TECHNOLOGY　212　(8)　1716-1722　2012/08

    DOI： 10.1016/j.jmatprotec.2012.03.010 　

    ISSN： 0924-0136

  134. The effect of scanning pitch of nozzle for a cavitating jet during overlapping peening treatment Peer-reviewed

    O. Takakuwa, H. Soyama

    SURFACE & COATINGS TECHNOLOGY　206　(23)　4756-4762　2012/07

    DOI： 10.1016/j.surfcoat.2012.03.034 　

    ISSN： 0257-8972

  135. Optimum Injection Pressure of a Cavitating Jet on Introduction of Compressive Residual Stress into Stainless Steel Peer-reviewed

    Hitoshi Soyama, Kazuya Nagasaka, Osamu Takakuwa, Akima Naito

    Journal of Power and Energy System　6　(2)　63-75　2012/06/29

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jpes.6.x 　

    ISSN： 1881-3062

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    Introducing compressive residual stress by a cavitating jet into the sub-surface of components used in nuclear power plants can mitigate stress corrosion cracking in these components. Although applying the jet is an effective method for this purpose, it should be used without causing damage to the surface from water jet droplets arising from high-pressure injection of the water jet. Thus, in introducing compressive residual stress, the injection pressure needs to be optimized. In this paper, in order to determine the optimum injection pressure, the residual stress of stainless steel treated by a jet at various injection pressures was measured using an X-ray diffraction method. The injection pressure of the jet was varied from 5 MPa to 300 MPa, and the diameter of the nozzle throat of the jet was varied from 0.35 mm to 2.0 mm. The variation of residual stress with depth was measured by alternating X-ray diffraction measurements with electropolishing. It was revealed that a cavitating jet at an injection pressure of 10 MPa with a nozzle diameter of 2.0 mm can introduce higher compressive residual stress to deeper into stainless steel compared with a jet at 300 MPa with a nozzle diameter of 0.35 mm when the downstream pressure of the nozzle was constant.

  136. Evaluation of Equibiaxial Compressive Stress Introduced into Austenitic Stainless Steel Using an Eddy Current Method Peer-reviewed

    Yuichi Sekine, Hitoshi Soyama

    JOURNAL OF NONDESTRUCTIVE EVALUATION　31　(2)　99-107　2012/06

    DOI： 10.1007/s10921-011-0125-5 　

    ISSN： 0195-9298

  137. Rolling Contact Fatigue Life of Steel Rollers Treated by Cavitation Peening and Shot Peening Peer-reviewed

    Masanori SEKI, Hitoshi SOYAMA, Yuji KOBAYASHI, Daisuke GOWA, Masahiro FUJII

    Journal of Solid Mechanics and Materials Engineering　6　(6)　478-486　2012/06

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jmmp.6.478 　

    ISSN： 1880-9871

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    The purpose of this study is to investigate the influence of peening on the rolling contact fatigue (RCF) life of steel rollers. First, steel rollers were treated by three types of peenings to ensure the same surface roughness of peened rollers. One is the cavitation peening (CP) used a cavitating jet in water with an injection pressure of 30 MPa, and the others are the fine particle peening (FPP) with a shot diameter of 0.1 mm and the normal shot peening (NSP) with a shot diameter of 0.3 mm. The surface hardness and the surface compressive residual stress of the steel rollers were increased by all the peenings. In particular, they were most increased by the FPP. On the other hand, the work-hardened depth due to the CP and the NSP was larger than that due to the FPP. As a result of the RCF tests, the RCF lives of the steel rollers were improved by all the peenings, and they were most improved by the NSP. Judging from the pmax - N curves and the [A(σy/√3 HV)]max - N curves, the improvement in RCF lives due to the FPP depended heavily on the increase in surface hardness due to that, and the effects of the CP and the NSP on the RCF were equivalent under the same surface roughness and the same surface hardness. It follows from these that the surface treatment condition should be selected according to the rolling contact conditions and the failure modes of machine elements.

  138. Using an indentation test to evaluate the effect of cavitation peening on the invasion of the surface of austenitic stainless steel by hydrogen Peer-reviewed

    O. Takakuwa, H. Soyama

    SURFACE & COATINGS TECHNOLOGY　206　(18)　3747-3750　2012/05

    DOI： 10.1016/j.surfcoat.2012.03.027 　

    ISSN： 0257-8972

  139. Suppression of hydrogen-assisted fatigue crack growth in austenitic stainless steel by cavitation peening Peer-reviewed

    O. Takakuwa, H. Soyama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY　37　(6)　5268-5276　2012/03

    DOI： 10.1016/j.ijhydene.2011.12.035 　

    ISSN： 0360-3199

    eISSN： 1879-3487

  140. Using an eddy current method with inverse analysis to determine the thickness of the layer modified by cavitation peening at the surface of type 316 L austenitic stainless steel Peer-reviewed

    Yuichi Sekine, Hitoshi Soyama

    NDT & E INTERNATIONAL　46　94-99　2012/03

    DOI： 10.1016/j.ndteint.2011.11.005 　

    ISSN： 0963-8695

  141. Evaluation of Stress Anisotropy and Shearing Stress Using an Eddy Current Method with a Tangential-Rectangular Coil Peer-reviewed

    Y. Sekine, H. Soyama

    Journal of Solid Mechanics and Materials Engineering　6　(3)　201-212　2012/03

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jmmp.6.201 　

    ISSN： 1880-9871

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    In establishing a system to evaluate residual stress, it is important to design the system so that it can also evaluate the stress anisotropy, since this is introduced into metallic materials by surface processes such as grinding and polishing. The shearing stress is also an important parameter when the shear strength has to be considered, since tensile stress can cause stress corrosion cracking. Thus, a method to nondestructively evaluate the stress anisotropy and shearing stress in a short time is required. In this paper, a nondestructive eddy current method using a tangential-rectangular coil was used to accomplish this. The material under test was stainless steel, Japanese Industrial Standard (JIS) SUS316L, ground or polished by an angle grinder. The stress anisotropy caused by the grinding and polishing processes was evaluated by the eddy current method with the tangential-rectangular coil. To vary the stress state, some specimens were treated with cavitation peening after grinding with the angle grinder. The results demonstrate that the stress anisotropy, shearing stress and peening intensity can be evaluated by the eddy current method using the tangential-rectangular coil. From the results, it was concluded that the maximum shearing stress and the direction of the principal stress could be determined.

  142. Development of peening technique using recirculating shot accelerated by water jet Peer-reviewed

    A. Naito, O. Takakuwa, H. Soyama

    MATERIALS SCIENCE AND TECHNOLOGY　28　(2)　234-239　2012/02

    DOI： 10.1179/1743284711Y.0000000027 　

    ISSN： 0267-0836

  143. Numerical simulation of the effects of residual stress on the concentration of hydrogen around a crack tip Peer-reviewed

    O. Takakuwa, M. Nishikawa, H. Soyama

    SURFACE & COATINGS TECHNOLOGY　206　(11-12)　2892-2898　2012/02

    DOI： 10.1016/j.surfcoat.2011.12.018 　

    ISSN： 0257-8972

  144. Measurement of the residual stress distribution of SUS316L stainless steel using an eddy current method Peer-reviewed

    Yuichi Sekine, Hitoshi Soyama

    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A　78　(789)　656-659　2012

    DOI： 10.1299/kikaia.78.656 　

    ISSN： 0387-5008

  145. Fatigue Strength of Steel Rollers and Gears Treated by Cavitation Peening with Short Processing Time Peer-reviewed

    Masanori Seki, Naruto Nishie, Seiya Kozai, Masamitsu Kakuda, Hitoshi Soyama, Akima Naito, Masahiro Fujii

    JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING　6　(1)　33-43　2012

    DOI： 10.1299/jamdsm.6.33 　

    ISSN： 1881-3054

  146. Suppression of Hydrogen Embrittlement in Stainless Steel by Re-Circulating Shot Peening Method Using a Water Jet Peer-reviewed

    Akima NAITO, Osamu TAKAKUWA, Hitoshi SOYAMA

    Jet Flow Engineering　28　(2)　12-17　2011/11/01

    Publisher:

    ISSN： 1341-3279

  147. Enhancing the Aggressive Intensity of a Cavitating Jet by Means of the Nozzle Outlet Geometry Peer-reviewed

    H. Soyama

    JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME　133　(10)　101301-1-101301-11　2011/10

    DOI： 10.1115/1.4004905 　

    ISSN： 0098-2202

  148. Thickness Determination of the Surface Modified Layer and the Distribution of Electromagnetic Properties Treated after Cavitation Peening Evaluated by an Eddy Current Method and Inverse Problem Using a Response Surface Peer-reviewed

    Y. Sekine, H. Soyama

    Proceedings of ATEM'11　2011　(10)　"OS17F022-1"-"OS17F022-9"　2011/09/19

    Publisher: The Japan Society of Mechanical Engineers

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    The thickness of the surface modified layer affects the mechanical properties like as corrosive and tribological properties. Thus, the thickness determination of surface modified layer is effective method for the evaluation of the peening efficiency, and nondestructive evaluating method is required. The variations of the depth distribution of residual stress and microstructure after peening make the change of electromagnetic properties like as magnetic permeability and electrical conductivity. The thickness of the surface modified layer can be evaluated using the variation of the electromagnetic properties after peening nondestructively. In the present paper, the thickness of the surface modified layer was determined by means of an eddy current method which can use for various metallic materials and inverse problem using a response surface which is using the experimental design method. From the results, the estimated thickness determined by the eddy current method and inverse problem related with the measured thickness determined by an X-ray diffraction method.

  149. Rolling Contact Fatigue Life of Steel Rollers Treated by Cavitation Peening and Shot Peening Peer-reviewed

    M. Seki, H. Soyama, Y. Kobayashi, D. Gowa, M. Fujii

    Proceedings of ATEM'11　6　(6)　478-486　2011/09/19

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jmmp.6.478 　

    ISSN： 1880-9871

    More details Close

    The purpose of this study is to investigate the influence of peening on the rolling contact fatigue (RCF) life of steel rollers. First, steel rollers were treated by three types of peenings to ensure the same surface roughness of peened rollers. One is the cavitation peening (CP) used a cavitating jet in water with an injection pressure of 30 MPa, and the others are the fine particle peening (FPP) with a shot diameter of 0.1 mm and the normal shot peening (NSP) with a shot diameter of 0.3 mm. The surface hardness and the surface compressive residual stress of the steel rollers were increased by all the peenings. In particular, they were most increased by the FPP. On the other hand, the work-hardened depth due to the CP and the NSP was larger than that due to the FPP. As a result of the RCF tests, the RCF lives of the steel rollers were improved by all the peenings, and they were most improved by the NSP. Judging from the pmax - N curves and the [A(σy/√3 HV)]max - N curves, the improvement in RCF lives due to the FPP depended heavily on the increase in surface hardness due to that, and the effects of the CP and the NSP on the RCF were equivalent under the same surface roughness and the same surface hardness. It follows from these that the surface treatment condition should be selected according to the rolling contact conditions and the failure modes of machine elements.

  150. Effect of Injection Pressure and Size of Nozzle Throat of a Cavitating Jet on Cavitation Peening Peer-reviewed

    H. Soyama, O. Takakuwa, A. Naito

    Proceedings of International Conference on Shot Peening　129-134　2011/09/13

  151. Technique for partially strengthening electrical steel sheet of IPM motor using cavitation peening Peer-reviewed

    O. Takakuwa, M. Nishikawa, H. Soyama

    MATERIALS SCIENCE AND TECHNOLOGY　27　(9)　1422-1426　2011/09

    DOI： 10.1179/026708310X12712410311695 　

    ISSN： 0267-0836

  152. Evaluation of the enhanced cavitation impact energy using a PVDF transducer with an acrylic resin backing Peer-reviewed

    Hitoshi Soyama, Yuichi Sekine, Kenichi Saito

    MEASUREMENT　44　(7)　1279-1283　2011/08

    DOI： 10.1016/j.measurement.2011.03.027 　

    ISSN： 0263-2241

  153. Two-step method to evaluate equibiaxial residual stress of metal surface based on micro-indentation tests Peer-reviewed

    Masaaki Nishikawa, Hitoshi Soyama

    Materials and Design　32　(6)　3240-3247　2011/06

    DOI： 10.1016/j.matdes.2011.02.044 　

    ISSN： 0264-1275 1873-4197

    eISSN： 1873-4197

  154. Enhancement of Aggressivity of Cavitating Jet and Its Practical Application Peer-reviewed

    Hitoshi Soyama, Osamu Takakuwa

    Journal of Fluid Science and Technology　6　(4)　510-521　2011/06

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jfst.6.510 　

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    A cavitating jet is a useful tool for the practical application of cavitation. Cavitation impact arises when bubbles collapse and can be utilized to modify the surfaces of materials as an alternative to shot peening. Peening methods using cavitation impact are called &ldquo;cavitation peening&rdquo; or &ldquo;cavitation shotless peening&rdquo;, as shot is not required. In cavitation peening, cavitation is generated by injecting a high-speed water jet into water, i.e., a cavitating jet. In practical applications, it is very important to maximize the aggressive strength of the jet. In the present paper, in order to do this, the outlet geometry of the nozzle of a cavitating jet was optimized. High-speed observations were carried out to investigate any instability in the jet. The introduction of compressive residual stress into stainless steel was demonstrated to show the effect of cavitation peening. Scaling- and velocity-effects, i.e., the effect of the injection pressure, at the nozzle throat was also examined. It was shown that a large cavitating jet at low injection pressure was more aggressive than a small jet at high injection pressure, for the same power.

  155. Two-step method to evaluate equibiaxial residual stress of metal surface based on micro-indentation tests Peer-reviewed

    Masaaki Nishikawa, Hitoshi Soyama

    MATERIALS & DESIGN　32　(6)　3240-3247　2011/06

    DOI： 10.1016/j.matdes.2011.02.044 　

    ISSN： 0261-3069

  156. Corrosion Behavior of Pressure Vessel Steel Exposed to Residual Bubbles After Cavitation Bubble Collapse Peer-reviewed

    H. Soyama

    CORROSION　67　(2)　025001-1-025001-8　2011/02

    DOI： 10.5006/1.3548733 　

    ISSN： 0010-9312

  157. Introduction of compressive residual stress into stainless steel by employing a cavitating jet in air Peer-reviewed

    Hitoshi Soyama, Tsutomu Kikuchi, Masaaki Nishikawa, Osamu Takakuwa

    SURFACE & COATINGS TECHNOLOGY　205　(10)　3167-3174　2011/02

    DOI： 10.1016/j.surfcoat.2010.11.031 　

    ISSN： 0257-8972

  158. Suppression of fatigue crack growth in austenite stainless steel by cavitation peening Peer-reviewed

    Osamu Takakuwa, Masaaki Nishikawa, Hitoshi Soyama

    ADVANCES IN FRACTURE AND DAMAGE MECHANICS IX　452-453　641-644　2011

    DOI： 10.4028/www.scientific.net/KEM.452-453.641 　

    ISSN： 1013-9826

  159. Suppression of fatigue crack propagation with hydrogen embrittlement in stainless steel by cavitation peening Peer-reviewed

    Osamu Takakuwa, Toshihito Ohmi, Masaaki Nishikawa, A. Toshimitsu Yokobori Jr., Hitoshi Soyama

    Strength, Fracture and Complexity　7　(1)　79-85　2011

    DOI： 10.3233/SFC-2011-0126 　

    ISSN： 1567-2069

  160. Luminescent spots induced by a cavitating jet Peer-reviewed

    Hitoshi Soyama

    ASME-JSME-KSME 2011 Joint Fluids Engineering Conference, AJK 2011　2　243-250　2011

    DOI： 10.1115/AJK2011-33018 　

  161. Chemical Reactor Using Radical Induced by a Cavitating Jet Peer-reviewed

    Hitoshi Soyama, Taka Muraoka

    Proceedings of 20th International Conference on Water Jetting　259-267　2010/10/20

  162. Sustainable surface modification using cavitation impact for enhancing fatigue strength demonstrated by a power circulating-type gear tester Peer-reviewed

    Hitoshi Soyama, Yuichi Sekine

    International Journal of Sustainable Engineering　3　(1)　25-32　2010/03

    DOI： 10.1080/19397030903395174 　

    ISSN： 1939-7038 1939-7046

  163. Evaluation of yield stress distribution in the surface layer and fatigue properties of the stainless steel modified by cavitation peening Peer-reviewed

    Masaaki Nishikawa, Osamu Takakuwa, Hitoshi Soyama

    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A　76　(770)　1367-1372　2010

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaia.76.1367 　

    ISSN： 0387-5008

  164. Effect of high strain-rate deformation on surface mechanical properties of stainless steel after peening Peer-reviewed

    Shinya Kanou, Masaaki Nishikawa, Hitoshi Soyama

    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A　76　(772)　1775-1780　2010

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaia.76.1775 　

    ISSN： 0387-5008

  165. A method to identify the yield stress of metals using micro-indentation tests with a spherical indenter Peer-reviewed

    Masaaki Nishikawa, Yusuke Kawaragi, Hitoshi Soyama

    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A　76　(772)　1781-1788　2010

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaia.76.1781 　

    ISSN： 0387-5008

  166. Comparison of Abilities of Various Cavitating Jets Peer-reviewed

    H. Soyama, K. Nishizawa, M. Mikami

    Water Jetting Technology for LOHAS, International Academic Printing Co., Ltd.　133-137　2009/11/21

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    Edited by S. Shimizu and G. Peng

  167. Fretting Fatigue Behavior of Cavitation Shotless Peened Ti-6Al-4V Peer-reviewed

    Hyukjae Lee, Shankar Mall, Hitoshi Soyama

    TRIBOLOGY LETTERS　36　(2)　89-94　2009/11

    DOI： 10.1007/s11249-009-9463-1 　

    ISSN： 1023-8883

  168. Surface Modification of Alloy Tool Steel for Forging Dies by Cavitation Peening Peer-reviewed

    Y. Sekine, H. Soyama

    Review of Automotive Engineering　30　(4)　393-399　2009/10

    DOI： 10.11351/jsaereview.30.393 　

  169. Enhancement of Cavitation Aggressivity around a Cavitating Jet by Injecting Low-Speed Water Jet for Cavitation Peening Peer-reviewed

    Hitoshi SOYAMA, Kazuto NISHIZAWA, Mitsuhiro MIKAMI

    Proceedings of 7th International Symposium on Cavitation　(Paper No. 12)　1-10　2009/08/17

  170. A microwave probe nanostructure for atomic force microscopy Peer-reviewed

    Y. Ju, M. Hamada, T. Kobayashi, H. Soyama

    MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS　15　(8)　1195-1199　2009/08

    DOI： 10.1007/s00542-009-0782-9 　

    ISSN： 0946-7076

    eISSN： 1432-1858

  171. Surface Modification of Alloy Tool Steel for Forging Die by Cavitation Shotless Peening Peer-reviewed

    関根 裕一, 祖山 均

    自動車技術会論文集　40　(3)　861-866　2009/05

  172. Evaluation of the surface of alloy tool steel treated by cavitation shotless peening using an eddy current method Peer-reviewed

    Yuichi Sekine, Hitoshi Soyama

    SURFACE & COATINGS TECHNOLOGY　203　(16)　2254-2259　2009/05

    DOI： 10.1016/j.surfcoat.2009.02.018 　

    ISSN： 0257-8972

  173. ノズル出口形状によるキャビテーション噴流まわりの衝撃力の強力化 Invited Peer-reviewed

    祖山 均, 西澤 一登

    混相流　混相流研究の進展4　77-85　2009/03/15

    Publisher: THE JAPANESE SOCIETY FOR MULTIPHASE FLOW

    DOI： 10.3811/pmfr.4.77 　

    ISSN： 1881-5804

    More details Close

    Impact force around a cavitating jet can be utilized for surface modification to improve fatigue strength of metallic materials. A peening method by cavitation impacts is called cavitation shotless peening (CSP), as shots are not required. For making practical use of CSP, enhancement of capability of the cavitating jet is required. In the present paper, an optimum nozzle outlet geometry that the mass loss shows the maximum was found by changing the nozzle outlet geometry through erosion test. In addition, the discharge frequency of cavitation clouds, Strouhal number and cavitation impacts by changing with nozzle outlet geometry were measured. It was revealed that nozzle outlet geometry affected the capability of the cavitating jet, the frequency of impacts, Strouhal number and the maximum value of cavitation impact force.

  174. Growth and proliferation of bone marrow mesenchymal stem cells affected by type I collagen, fibronectin and bFGF Peer-reviewed

    Guanbin Song, Yang Ju, Hitoshi Soyama

    MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS　28　(8)　1467-1471　2008/12

    DOI： 10.1016/j.msec.2008.04.005 　

    ISSN： 0928-4931

  175. Release of Micro Strain in Tool Alloy Steel by a Cavitating Jet in Air Peer-reviewed

    H.Soyama, N.Yamada, O.Takakuwa, Y.Sekine, M.Mikami

    Proceedings of 19th International Conference on Water Jetting　219-228　2008/10/15

  176. Visualization of the plastic deformation area beneath the surface of carbon steel induced by cavitation impact Peer-reviewed

    A. Kai, H. Soyarna

    SCRIPTA MATERIALIA　59　(3)　272-275　2008/08

    DOI： 10.1016/j.scriptamat.2008.02.054 　

    ISSN： 1359-6462

  177. Improving the fatigue strength of the elements of a steel belt for CVT by cavitation shotless peening Peer-reviewed

    Hitoshi Soyama, Masanori Shimizu, Yuji Hattori, Yuji Nagasawa

    JOURNAL OF MATERIALS SCIENCE　43　(14)　5028-5030　2008/07

    DOI： 10.1007/s10853-008-2743-6 　

    ISSN： 0022-2461

    eISSN： 1573-4803

  178. Relieving micro-strain by introducing macro-strain in a polycrystalline metal surface by cavitation shotless peening Peer-reviewed

    H. Soyama, N. Yamada

    MATERIALS LETTERS　62　(20)　3564-3566　2008/07

    DOI： 10.1016/j.matlet.2008.03.055 　

    ISSN： 0167-577X

    eISSN： 1873-4979

  179. Development of a nanostructural microwave probe based on GaAs Peer-reviewed

    Y. Ju, T. Kobayashi, H. Soyama

    MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS　14　(7)　1021-1025　2008/07

    DOI： 10.1007/s00542-007-0484-0 　

    ISSN： 0946-7076

    eISSN： 1432-1858

  180. Reduction of Young's Modulus of Surface Modification Layer of Stainless Steel SUS316L by Cavitation Shotless Peening Peer-reviewed

    Yuichi Sekine, Akira Kai, Hitoshi Soyama

    Transactions of the Japan Society of Mechanical Engineers　74A　(742)　901-908　2008/06/25

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaia.74.901 　

    ISSN： 0387-5008

    More details Close

    Peening is a technique of surface modification to improve fatigue strength of metallic materials. Cavitation shotless peening (CSP) is the peening method using cavitation impacts and shots are not required. Residual stress and hardness of materials are also changed by CSP. Similarly, Young's modulus of surface improvement layer might be changed by CSP. Young's modulus is one of the main mechanical properties of materials, and indicates material structure, and it is an important parameter for stress measurement by X-ray diffraction. In the present paper, Young's modulus of type 316 L stainless steel peened by CSP was evaluated by measuring natural frequency of cantilever. And, Young's modulus of surface modification layer is evaluated by assuming composite cantilever. It was revealed that Young's modulus of surface modification layer by CSP was decreased about 11%, although Vickers hardness was increased about 40%. Namely, elastically hardness is decreased, and plastically hardness is increased by CSP.

  181. Introduction of macro-strain with releasing micro-strain by cavitation shotless peening Invited Peer-reviewed

    Hitoshi Soyama

    INTERNATIONAL JOURNAL OF MODERN PHYSICS B　22　(9-11)　1680-1685　2008/04

    DOI： 10.1142/S0217979208047250 　

    ISSN： 0217-9792

    eISSN： 1793-6578

  182. 1413 Release of Micro Strain Introducing Compressive Residual Stress by Cavitation Shotless Peening

    TAKAKUWA Osamu, SOYAMA Hitoshi

    The proceedings of the JSME annual meeting　2008　233-234　2008

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemecjo.2008.1.0_233 　

    More details Close

    Impacts at cavitation bubble collapses can be utilized for surface modification in the same way as shot peening. Peening method using cavitation impact was called "cavitation shotless peening (CSP)" as shots were not required. Peening is one of the techniques of surface modification to introduce compressive residual stress to improve fatigue strength of metallic materials and to reduce stress corrosion cracking (SCC). At the same time, CSP can release micro strain introduced mechanical finishing or heat treatment, introducing compressive residual stress in the material. There is a possibility that the large residual stress exists in micro-meter subsurface where less 10 μm from surface and 2D method using 2D detector can evaluate residual stress in sub-surface of polycrystalline metallic materials. Full width at half maximum of X-ray diffraction (FWHM) is closely related to micro strain in grain. In the present paper, stainless steel and Inconel were treated by CSP and residual stress and FWHM were evaluated. It was revealed that CSP decreased FWHM with introducing compressive residual stress in micro-meter subsurface.

  183. A Nanostructual Microwave Probe Used for Atomic Force Microscope Peer-reviewed

    Y. Ju, M. Hamada, T. Kobayashi, H. Soyama

    DTIP 2008: SYMPOSIUM ON DESIGN, TEST, INTEGRATION AND PACKAGING OF MEMS/MOEMS　158-+　2008

  184. Rolling Contact Fatigue Life of Cavitation-Peened Steel Gear Peer-reviewed

    Masanori Seki, Hitoshi Soyama, Masahiro Fujii, Akira Yoshida

    Tribology Online　3　(2)　116-121　2008

    Publisher: Japanese Society of Tribologists

    DOI： 10.2474/trol.3.116 　

    ISSN： 1881-2198

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    The purpose of this study is to investigate the effect of cavitation peening on the rolling contact fatigue life of steel gears. The steel rollers and gears cavitation-peened under different conditions were fatigue-tested using a roller testing machine and a gear testing machine. After the cavitation peening, the surface hardness and the surface compressive residual stress of the steel rollers and gears were increased. On the other hand, the surface roughness was not increased so much. As a result, the fatigue life of most cavitation-peened rollers and gears was longer than that of the non-peened ones. In particular, the fatigue life was significantly improved by using a modified nozzle for a high-speed water jet to obtain a greater peening effect. It is suggested from these that the cavitation peening is good for the increase in fatigue life of steel gears, because the peening effect is obtained with less increase of the surface roughness.

  185. Improvement of the Fatigue Strength of Stainless Steel SUS316L by a Cavitating Jet with an Associated Water Jet in Water Peer-reviewed

    Hitoshi Soyama, Yuichi Sekine, Yosuke Oyama

    ISIJ INTERNATIONAL　48　(11)　1577-1581　2008

    DOI： 10.2355/isijinternational.48.1577 　

    ISSN： 0915-1559

    eISSN： 1347-5460

  186. Improvement of fatigue strength by using cavitating jets in air and water Peer-reviewed

    H. Soyama

    JOURNAL OF MATERIALS SCIENCE　42　(16)　6638-6641　2007/08

    DOI： 10.1007/s10853-007-1535-8 　

    ISSN： 0022-2461

  187. Regulation of Cyclic Longitudinal Mechanical Stretch on Proliferation of Human Bone Marrow Mesenchymal Stem Cells Peer-reviewed

    G. Song, Y. Ju, H. Soyama, T. Ohashi, M. Sato

    Molecular & Cellular Biomechanics　4　(4)　201-210　2007/04

  188. 2720 Visualization of Plastic Deformation Area at the Metal Surface Pit Caused by the Cavitation Impact

    KAI Akira, SOYAMA Hitoshi

    The proceedings of the JSME annual meeting　2007　601-602　2007

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemecjo.2007.1.0_601 　

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    The impact caused by cavitation bubble collapse can be applied to the peening of the metallic material due to introducing compressive stress and plastic deformation at the surface. The improvement of fatigue strength of the metallic material by cavitation impact is almost as same as that of conventional shot peening. However, it has been reported that both thickness and residual stress level of the modified layer by the cavitation impact are smaller than those of the shot peening. In the present report, in order to clarify the formation of the plastic deformation area caused by cavitation impact, a visualization using the fry etching method was conducted. It is elucidated that the shape of plastic deformation area beneath the pit is different from that of the dent caused by Hertz contact using spherical indenter. In the case of sufficient treatment using cavitation impact the uneven boundary between the modified layer and the substrate was observed.

  189. 2401 Evaluation of Young's Modulus of Surface Improvement Layer Using Natural Frequency of Cantilever

    SEKINE Yuichi, KAI Akira, SOYAMA Hitoshi

    The proceedings of the JSME annual meeting　2007　377-378　2007

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemecjo.2007.1.0_377 　

    More details Close

    Peening is the technique of surface modification to improve fatigue strength of metallic materials. Cavitation shotless peening (CSP) is the peening method using cavitation impact and does not required shots. Young's Modulus of surface improvement layer might be changed by peening. Young's modulus is one of the main mechanical properties of materials and shows material structure. In the present paper, the evaluation method of Young's modulus of the surface improvement layer was proposed. Both sides of cantilever were peened by CSP changing with peening time, and the natural frequency of this cantilever was measured, and then, Young's modulus was evaluated. We revealed that Young's modulus of the cantilevers peened by CSP was changed.

  190. Improvement of fatigue strength of stainless steel by using a cavitating jet with an associated water jet in water Peer-reviewed

    Hitoshi Soyama, Mitsuhiro Mikami

    PROGRESSES IN FRACTURE AND STRENGTH OF MATERIALS AND STRUCTURES, 1-4　353-358　162-+　2007

    ISSN： 1013-9826

  191. Quantitative evaluation of cracks under water by microwaves Peer-reviewed

    Yang Ju, Toru Miyadu, Hitoshi Soyama, Masumi Saka

    PROGRESSES IN FRACTURE AND STRENGTH OF MATERIALS AND STRUCTURES, 1-4　353-358　2361-2365　2007

    ISSN： 1013-9826

  192. Characterization of Polysilicon Thin Films for MEMS Applications

    Dan O. Macodiyo, Hitoshi Soyama, Kazuo Hayashi

    WSEAS Transactions on Systems　5　(10)　2418-2422　2006/10

  193. Cavitation Erosion of Pure Titunium (TB340H) and Stainless Steel (SUS316L) in Sea Water Peer-reviewed

    望月 敬美, 横田 源弘, 祖山 均, 服部 修次

    日本機械学会論文集（A編）　72　(721)　1370-1375　2006/09

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaia.72.1370 　

    ISSN： 0387-5008

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    Cavitation erosion was studied for pure tianium (TB270H, TB340H, TP49H) and stainless steel (SUS316L) samples using a rotating disk apparatus in seawater and tap water. In addition, identical experiments for titanium alloy (Ti-6Al-V, Ti-15V-3Cr-3Cn-3Al) samples were carried out in salt water (3%) and ion exchange water using a vibratory apparatus. Erosion resistance of pure titanium in seawater is excellent, as it is in tap water, but the incubation period in seawater is shorter than that in tap water. Erosion resistance of stainless steel is excellent in tap water, but it is necessary to advance the time for its inspection when stainless steel is used for the seawater pump impeller material because the resistance decreases remarkably in seawater. Normalized erosion resistance of these metals using a rotating disk and a vibratory apparatus can be evaluated similarly in terms of Vickers hardness (HV) when it is arranged using a standard material.

  194. Optimization of cavitation peening parameters for fatigue performance of carburized steel using Taguchi methods Peer-reviewed

    Dan O. Macodiyo, Hitoshi Soyama

    JOURNAL OF MATERIALS PROCESSING TECHNOLOGY　178　(1-3)　234-240　2006/09

    DOI： 10.1016/j.jmatprotec.2006.03.172 　

    ISSN： 0924-0136

  195. Microdefects induced by cavitation for gettering in silicon wafer Peer-reviewed

    Dan O. Macodiyo, Hitoshi Soyama, Takashi Masakawa, Kazuo Hayashi

    JOURNAL OF MATERIALS SCIENCE　41　(16)　5380-5382　2006/08

    DOI： 10.1007/s10853-006-0144-2 　

    ISSN： 0022-2461

    eISSN： 1573-4803

  196. A Prediction Method of Incubation Period on Cavitation Erosion Peer-reviewed

    祖山 均, 二川 正敏, 直江 崇

    ターボ機械　34　(6)　336-342　2006/08

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj.34.336 　

    ISSN： 0385-8839

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    Japan Atomic Energy Agency and High Energy Accelerator Research Organization are constructing a MW-scale neutron source system, which will use liquid-mercury as a target material for spallation and to cool the target vessel in Japan Proton Accelerator Research Complex (J-PARC). The severe cavitation erosion may occur in the vessel of the target and it is necessarily to predict the life time of the target vessel, which is exposed to cavitation impact. As the target vessel is very thin and experimental erosion data induced by proton beam is very few, it is required to estimate the incubation period by a few points. The prediction method of incubation period has been proposed. In order to estimate cavitation erosion intensity on the target, an off-line test, which is modified on-beam test, was carried out. Measuring the cavitation intensity of the off-line test using a laser Doppler vibrometer, the relation between the cavitation intensity and developing time of cavitation bubble was found. The relation revealed a similarity law on scaling effect of cavitation erosion, which can be applied to cavitation erosion of pumps and turbines.

  197. Estimation of cavitation intensity from the time taken for bubbles to develop Peer-reviewed

    H. Soyama, M. Futakawa

    TRIBOLOGY LETTERS　23　(1)　23-26　2006/07

    DOI： 10.1007/s11249-006-9114-8 　

    ISSN： 1023-8883

  198. 3620 Improvement of Fatigue Strength of Light Metallic Materials by Cavitation Peening

    SOYAMA Hitoshi, MIYAMOTO Noritaka

    The proceedings of the JSME annual meeting　2006　777-778　2006

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemecjo.2006.1.0_777 　

    More details Close

    Cavitation normally causes severe damage in hydraulic machinery such as pumps and valves so on. However, cavitation impact can be utilized to surface treatment to improve fatigue strength of metallic materials in the same way as shot peening. Peening using cavitation impact was named as "cavitation peening" or "cavitation shotless peening" as shots are not required. As increase of surface roughness induced by cavitation peening was relatively small comparing with that of shot peening, improvement of fatigue strength of light metallic materials would be better than that of shot peening. In the present paper, the aluminum alloy and the magnesium alloy treated by cavitation peening were tested by a rotating bending fatigue test. It was revealed that the fatigue strength of the aluminum alloy AC4CH and magnesium alloy AM60B were improved 40% and 20%, respectively.

  199. Characterization of defects for effective gettering in silicon wafer and polysilicon thin films Peer-reviewed

    Dan O. Macodiyo, Hitoshi Soyama, Kazuo Hayashi

    PROCEEDINGS OF THE 8TH BIENNIAL CONFERENCE ON ENGINEERING SYSTEMS DESIGN AND ANALYSIS, VOL 2　963-972　2006

  200. High-speed observation of a cavitating jet in air Peer-reviewed

    H Soyama

    JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME　127　(6)　1095-1101　2005/11

    DOI： 10.1115/1.2060737 　

    ISSN： 0098-2202

  201. Contactless measurement of electrical conductivity of Si wafers independent of wafer thickness Peer-reviewed

    Y Ju, Y Hirosawa, H Soyama, M Saka

    APPLIED PHYSICS LETTERS　87　(16)　162102-1-162102-3　2005/10

    DOI： 10.1063/1.2105992 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  202. Pitting damage by pressure waves in a mercury target Peer-reviewed

    M Futakawa, T Naoe, CC Tsai, H Kogawa, S Ishikura, Y Ikeda, H Soyama, H Date

    JOURNAL OF NUCLEAR MATERIALS　343　(1-3)　70-80　2005/08

    DOI： 10.1016/j.jnucmat.2004.07.063 　

    ISSN： 0022-3115

  203. Estimation of pitting damage induced by cavitation impacts Peer-reviewed

    H Soyama, M Futakawa, K Homma

    JOURNAL OF NUCLEAR MATERIALS　343　(1-3)　116-122　2005/08

    DOI： 10.1016/j.jnucmat.2004.11.016 　

    ISSN： 0022-3115

    eISSN： 1873-4820

  204. キャビテーション噴流によりシリコンウェーハに導入したバックサイドダメージのX線回折による評価 Invited Peer-reviewed

    祖山 均, 齋藤 卓, ダン マコディヨ, 林 一夫

    噴流工学　22　(2)　18-22　2005/06

    Publisher:

    ISSN： 1341-3279

  205. Fatigue strength improvement of gears using cavitation shotless peening Peer-reviewed

    H Soyama, DO Macodiyo

    TRIBOLOGY LETTERS　18　(2)　181-184　2005/02

    DOI： 10.1007/s11249-004-1774-7 　

    ISSN： 1023-8883

    eISSN： 1573-2711

  206. 518 Distribution of Residual Stress around Plastic Deformation Pit Induced by Cavitation Shotless Peening

    Hitoshi SOYAMA

    Proceedings of the 1992 Annual Meeting of JSME/MMD　2005　361-362　2005

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmezairiki.2005.0_361 　

    eISSN： 2433-1287

  207. Fabrication of the tip of GaAs microwave probe by wet etching Peer-reviewed

    Yang Ju, Hiroyuki Sato, Hitoshi Soyama

    Advances in Electronic Packaging 2005, Pts A-C　1919-1922　2005

  208. Compressive residual stress into titanium alloy using cavitation shotless peening method Peer-reviewed

    H Soyama, DO Macodiyo, S Mall

    TRIBOLOGY LETTERS　17　(3)　501-504　2004/10

    DOI： 10.1023/B:TRIL.0000044497.45014.f2 　

    ISSN： 1023-8883

  209. Evaluation of the effectiveness of back-side damage gettering in silicon introduced by a cavitating jet Peer-reviewed

    H Kumano, T Sasaki, H Soyama

    APPLIED PHYSICS LETTERS　85　(17)　3935-3937　2004/10

    DOI： 10.1063/1.1808499 　

    ISSN： 0003-6951

  210. Estimation of incubation time of cavitation erosion for various cavitating conditions Peer-reviewed

    H Soyama, M Futakawa

    TRIBOLOGY LETTERS　17　(1)　27-30　2004/07

    DOI： 10.1023/B:TRIL.0000017415.79517.8c 　

    ISSN： 1023-8883

  211. Improvement of fatigue strength by using a cavitating jet in air

    H. Soyama, M. Mikami, K. Homma

    17th International Conference on Water Jetting: Advances and Future Needs　97-105　2004

  212. Contactless measurement of conductivity of silicon wafers by millimeter waves Peer-reviewed

    Y Ju, Y Hirosawa, H Soyama, M Saka

    MSMW'04: FIFTH INTERNATIONAL KHARKOV SYMPOSIUM ON PHYSICS AND ENGINEERING OF MICROWAVES, MILLIMETER, AND SUBMILLIMETER WAVES, SYMPOSIUM PROCEEDINGS, VOLS 1 AND 2　424-426　2004

  213. Gettering of Cu in silicon wafer by using cavitation impacts Peer-reviewed

    H Kumano, H Soyama, M Saka

    ADVANCES IN FRACTURE AND FAILURE PREVENTION, PTS 1 AND 2　261-263　1409-1413　2004

    ISSN： 1013-9826

  214. Evaluation of the damage for gettering in silicon wafer introduced by a cavitating jet Peer-reviewed

    H Kumano, H Soyama, M Saka

    ADVANCES IN FRACTURE AND FAILURE PREVENTION, PTS 1 AND 2　261-263　1403-1408　2004

    ISSN： 1013-9826

  215. Effect of cavitation number on the improvement of fatigue strength of carburized steel using cavitation shotless peening Peer-reviewed

    DO Macodiyo, H Soyama, M Saka

    ADVANCES IN FRACTURE AND FAILURE PREVENTION, PTS 1 AND 2　261-263　1245-1250　2004

    ISSN： 1013-9826

  216. Introduction of compressive residual stress using a cavitating jet in air Peer-reviewed

    H Soyama

    JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME　126　(1)　123-128　2004/01

    DOI： 10.1115/1.1631434 　

    ISSN： 0094-4289

  217. Electrical Characterization of Doped Silicon Using High-Frequency Electromagnetic Waves Peer-reviewed

    Yang Ju, Yasushi Ohno, Hitoshi Soyama, Masumi Saka

    Journal of Materials Science and Technology　20　(1)　1-2　2004/01

  218. Back side damage gettering of Cu using a cavitating jet Peer-reviewed

    H Kumano, H Soyama

    ELECTROCHEMICAL AND SOLID STATE LETTERS　7　(4)　G51-G52　2004

    DOI： 10.1149/1.1648614 　

    ISSN： 1099-0062

  219. Improvement of fatigue strength by using cavitating jet in air Peer-reviewed

    Hitoshi Soyama, Dan Macodiyo

    American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP　472　165-169　2004

    DOI： 10.1115/PVP2004-2988 　

    ISSN： 0277-027X

  220. Introduction of compressive residual stress into titanium alloy Ti6Al4V by cavitation shotless peening Peer-reviewed

    Hitoshi Soyama, Dan Odhiambo, Shankar Mall

    Zairyo/Journal of the Society of Materials Science, Japan　53　(8)　836-840　2004

    Publisher: Society of Materials Science Japan

    DOI： 10.2472/jsms.53.836 　

    ISSN： 0514-5163

  221. Quantitative evaluation of closed cracks on the surface of stainless steel by microwaves Peer-reviewed

    Yang Ju, Toru Miyadu, Yasuhiro Uchimura, Hitoshi Soyama, Masumi Saka

    Zairyo/Journal of the Society of Materials Science, Japan　53　(8)　900-905　2004

    Publisher: Society of Materials Science Japan

    DOI： 10.2472/jsms.53.900 　

    ISSN： 0514-5163

  222. Peen Forming by Using a Cavitating Jet in Air

    Hitoshi Soyama, Kenichi Saito

    Proceedings of the 7th Pacific Rim International Conference on Water Jetting Technology　429　429-436　2003/10

  223. Cavitation shotless peening for improvement of fatigue strength of carbonized steel Peer-reviewed

    D Odhiambo, H Soyama

    INTERNATIONAL JOURNAL OF FATIGUE　25　(9-11)　1217-1222　2003/09

    DOI： 10.1016/S0142-1123(03)00121-X 　

    ISSN： 0142-1123

  224. Improvement of Fatigue Strength on Duralumin by Cavitation Shotless Peening Peer-reviewed

    Dan O. Macodiyo, Hitoshi Soyama, Kenichi Saito, Masumi Saka

    Proceedings of International Conference on Advanced Technology in Experimental Mechanics 2003　CDROM　OS11W0131　2003/09

  225. Singularity of Half Width of X-ray Diffraction on Cavitation Shotless Peening

    Hitoshi Soyama, Dan O. Macodiyo

    Journal of Society of Shot Peening Technology of Japan　15　(3)　141-148　2003/09

  226. Cavitation shotless peening for surface modification of alloy tool steel Peer-reviewed

    H Soyama, K Sasaki, D Odhiambo, M Saka

    JSME INTERNATIONAL JOURNAL SERIES A-SOLID MECHANICS AND MATERIAL ENGINEERING　46　(3)　398-402　2003/07

    DOI： 10.1299/jsmea.46.398 　

    ISSN： 1344-7912

  227. Cavitation Shotless Peening for Improvement of Fatigue Strength

    Hitoshi Soyama, Dan Odhiambo, Kenichi Saito

    Proceedings of the 8th International Conference on Shot Peening　435-440　2003/02

  228. Improvement of Fatigue Strength of Stainless Steel by Using a Cavitating Jet in Air

    SOYAMA Hitoshi, Macodiyo Dan

    Proceedings of the 1992 Annual Meeting of JSME/MMD　2003　181-182　2003

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmezairiki.2003.0_181 　

  229. Relationship on Cavitation Shotless Peening between Residual Stress and Pressure Distribution of Cavitation Impact

    SOYAMA Hitoshi, SAITO Kenich

    The proceedings of the JSME annual meeting　2003　145-146　2003

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemecjo.2003.6.0_145 　

    More details Close

    Impacts induced by cavitation at bubble collapse can utilize to surface modification as same way as shot peening. This method is called as cavitation shotless peening (CSP), as shots are not required. As the mechanism of impact is completely different between shot peening and CSP, CSP has different effects from shot peening. For example, in case of introduction of compressive residual stress by shot peening, the compressive residual stress has a maximum at certain depth. Thus, in order to increase the compressive residual at the surface, multi-stage shot peening using different size of shot was required. However, CSP can introduce maximum compressive residual stress at the surface. This sort of effect depends on the pressure distribution of the impacts. In the present paper, the pressure distribution associated with introduction of compressive residual stress was investigated by measuring the plastic deformation pit on different hardness specimens.

  230. Recrystallization-etch observation of plastic deformation caused by cavitation shotless peening Peer-reviewed

    DO Macodiyo, H Soyama, M Saka

    JOURNAL OF MATERIALS SCIENCE LETTERS　22　(2)　115-117　2003/01

    DOI： 10.1023/A:1021858718994 　

    ISSN： 0261-8028

  231. Cavitation Shotless Peening for Improvement of Fatigue Strength of Metallic Materials Peer-reviewed

    H. Soyama, K. Sasaki, K. Saito, M. Saka

    Transactions of Society of Automotive Engineers of Japan　34　(1)　101-106　2003/01

  232. Localized-impact damage caused by proton bombarding in mercury target

    M. Futakawa, H. Kogawa, S. Ishikura, H. Kudo, H. Soyama

    Journal De Physique. IV : JP　110　583-588　2003

    Publisher: EDP Sciences

    DOI： 10.1051/jp4:20020756 　

    ISSN： 1155-4339

  233. The fundamental threshold level - A new parameter for predicting cavitation erosion resistance Peer-reviewed

    H Soyama, H Kumano

    JOURNAL OF TESTING AND EVALUATION　30　(5)　421-431　2002/09

    DOI： 10.1520/JTE12333J 　

    ISSN： 0090-3973

  234. Improvement of fatigue strength of aluminum alloy by cavitation shotless peening Peer-reviewed

    H Soyama, K Saito, M Saka

    JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME　124　(2)　135-139　2002/04

    DOI： 10.1115/1.1447926 　

    ISSN： 0094-4289

  235. Improvement of Fatigue Strength of Aluminum Alloy Casting by Cavitating Jet in the Air

    Proceedings of the 1992 Annual Meeting of JSME/MMD　2002　483-484　2002

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmezairiki.2002.0_483 　

  236. Evaluation of Peening Intensity of Cavitation Shotless Peening by Using Almen Strip Peer-reviewed

    H. Soyama, H. Kumano, K. Saito, M. Saka

    Proc. of APCFS & ATEM'01, JSME-MMD, October 20-22, 2001, Sendai, Japan　2　1047-1050　2001/10

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmeatemapcfs.2.01.03.0_1047 　

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    Cavitating jet can be used to strengthen metallic materials by introducing compressive residual stress into the surface in the same way as shot peening. This surface modification method is called "Cavitation shotless peening", since shot used in shot peening is not required and the impacts of cavitation babble collapses is utilized to peen the surface. In order to demonstrate the effectiveness of cavitation shotless peening, almen strip was exposed to the cavitating jet at several jet conditions. The almen strip is generally used for evaluation of the peening intensity of shot peening by measurement of whose arc height. The almen strip exposed to the cavitating jet bent and the arc height occurred depending upon the jet parameters such as cavitation number, standoff distance, and nozzle diameter. Two types of almen strip, A and N, having different thickness, were used in this study. In the case of cavitation shotless peening, the relation between arc height of thin almen strip and that of thick one was different from that of shot peening. Furthermore, the surface roughness of almen strip exposed to the cavitating jet was significantly smoother than that of shot peening. It is concluded that cavitation shotless peening is effective in the surface modification and that the peening intensity of cavitation shotless peening changing with cavitating jet conditions can be evaluated by using almen strip.

  237. Backside Damage Introduced by Cavitating Jet for Gettering Peer-reviewed

    H. Kumano, H. Soyama, M. Saka

    Proc. of IPACK'01, The Pacific Rim/ASME International Electronic Packaging Technical Conference and Exhibition, July 8-13, 2001, Kauai, Hawaii, USA (CD-ROM)　2001/07

  238. Possibility of Gettering in Silicon Wafer by Using a Cavitating Jet Peer-reviewed

    Hiroyuki KUMANO, Hitoshi SOYAMA, Masumi SAKA

    Journal of Jet Flow Engineering　18　(2)　4-9　2001/06

    Publisher:

    ISSN： 1341-3279

  239. Cavitating Jet Peening for the Improvement of Fatigue Strength Peer-reviewed

    Hitoshi SOYAMA, Kei SASAKI, Hiroyuki KUMANO, Masumi SAKA

    Materials Science Research International, Special Technical Publication　1　216-219　2001/05

  240. 316 Improvement of Fatigue Strength of Aluminum Alloy by Cavitation Shotless Peening

    SOYAMA Hitoshi, SAITO Kenichi, SASAKI Kei, SAKA Masumi

    Proceedings of the 1992 Annual Meeting of JSME/MMD　2001　261-262　2001

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmezairiki.2001.0_261 　

  241. Peening by the use of cavitation impacts for the improvement of fatigue strength Peer-reviewed

    H Soyama, T Kusaka, M Saka

    JOURNAL OF MATERIALS SCIENCE LETTERS　20　(13)　1263-1265　2001

    DOI： 10.1023/A:1010947528358 　

    ISSN： 0261-8028

  242. Shotless Peening of Tool Alloy Steel SKD61 by Using Cavitation Impacts

    H. Soyama, T. Kusaka, M. Saka

    Proc. International Workshop on Sensing and Evaluation of Materials System, ISRE 2000, August 18-25, Sendai, Japan　117-122　2000/08

  243. Compressive Residual Stress Introduced by Cavitation Impacts Peer-reviewed

    H. Soyama, T. Kusaka, M. Saka

    Proceedings of 6th International Conference on Residual Stresses　1　674-681　2000/07

  244. Improvement in fatigue strength of silicon manganese steel SUP7 by using a cavitating jet Peer-reviewed

    H Soyama

    JSME INTERNATIONAL JOURNAL SERIES A-SOLID MECHANICS AND MATERIAL ENGINEERING　43　(2)　173-178　2000/04

    DOI： 10.1299/jsmea.43.173 　

    ISSN： 1344-7912

  245. Use of cavitating jet for introducing compressive residual stress Peer-reviewed

    H Soyama, JD Park, M Saka

    JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME　122　(1)　83-89　2000/02

    DOI： 10.1115/1.538911 　

    ISSN： 1087-1357

  246. Oxidation-induced stacking faults introduced by using a cavitating jet for gettering in silicon Peer-reviewed

    H Soyama, H Kumano

    ELECTROCHEMICAL AND SOLID STATE LETTERS　3　(2)　93-94　2000/02

    DOI： 10.1149/1.1390968 　

    ISSN： 1099-0062

    eISSN： 1944-8775

  247. Improvement of the corrosion resistance of a carbon steel surface by a cavitating jet Peer-reviewed

    H Soyama, M Asahara

    JOURNAL OF MATERIALS SCIENCE LETTERS　18　(23)　1953-1955　1999/12

    DOI： 10.1023/A:1006605920430 　

    ISSN： 0261-8028

  248. Increase of Ability of Water Jet by Using Cavitation Impacts and Its Application to Peening of Material Peer-reviewed

    H. SOYAMA

    Journal of Jet Flow Engineering　16　(3)　22-28　1999/10

  249. Hybrid surface treatment of carbon steel by using a cavitating jet Peer-reviewed

    H Soyama, M Asahara, M Saka

    SURFACE TREATMENT IV　3　93-102　1999

    ISSN： 1466-7266

  250. A new calibration method for dynamically loaded transducers and its application to cavitation impact measurement International-coauthorship Peer-reviewed

    H Soyama, A Lichtarowicz, T Momma, EJ Williams

    JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME　120　(4)　712-718　1998/12

    DOI： 10.1115/1.2820728 　

    ISSN： 0098-2202

  251. Severe Cavitation Process in a High Specific Centrifugal Pump Peer-reviewed

    Shou-Ren Li, Hitoshi Soyama, Masashi Tonosaki, Kazuo Uranishi, Hiroharu Kato, Toshiaki Ikohagi, Risaburo Oba

    Turbomachinery　26　(12)　722-729　1998/12

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.26.722 　

    ISSN： 0385-8839

  252. Possibility of Suitable Low Flow Rate Operation in MC Slurry Pumps Peer-reviewed

    Shou-Ren Li, Takashi Ito, Akihiko Kakegawa, Hitoshi Soyama, Toshiaki Ikohagi, Risaburo Oba

    Turbomachinery　26　(10)　617-623　1998/10

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.26.617 　

    ISSN： 0385-8839

  253. Effect of Acoustic Emission upon the Unsteady Force of a Supercavitating-Foil Peer-reviewed

    Makoto Takahashi, Hitoshi Soyama, Osamu Kurisawa, Toshiaki Ikohagi, Nobuyuki Yoshikawa, Risaburo Oba

    Turbomachinery　26　(6)　332-337　1998/06

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.26.332 　

    ISSN： 0385-8839

  254. Useful Correlations for Cavitating Water Jet Peer-reviewed

    H. Soyama, A. Lichtarowicz

    Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu　7　1456-1458　1998

    DOI： 10.4131/jshpreview.7.1456 　

    ISSN： 1348-1940 0917-639X

  255. Improvement of residual stress in stainless steel by cavitating jet Peer-reviewed

    Hitoshi Soyama, Jung-Do Park, Masumi Saka, Hiroyuki Abé

    Zairyo/Journal of the Society of Materials Science, Japan　47　(8)　808-812　1998

    Publisher: Soc Mater Sci, Japan

    DOI： 10.2472/jsms.47.808 　

    ISSN： 0514-5163

  256. LDV Measurement of Unsteady Flows around Supercavitating Hydrofoils Peer-reviewed

    T. Ikohagi, M. Takahashi, O. Kurisawa, H. Ohara, H. Soyama, Y. Matsudaira, K. Takahashi, R. Oba

    Turbomachinery　25　(2)　90-96　1997/02

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.25.90 　

    ISSN： 0385-8839

  257. High-speed observation of ultrahigh-speed submerged water jets Peer-reviewed

    H Soyama, Y Yanauchi, K Sato, T Ikohagi, R Oba, R Oshima

    EXPERIMENTAL THERMAL AND FLUID SCIENCE　12　(4)　411-416　1996/05

    DOI： 10.1016/0894-1777(95)00124-7 　

    ISSN： 0894-1777

  258. Three Types of Vibrations on A Super Cavitating Hydrofoil Peer-reviewed

    H. Soyama, H. Naka, J. Abe, T. Miyagawa, M. Takahashi, T. Ikohagi, R. Oba

    Turbomachinery　24　(4)　200-204　1996/04

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.24.200 　

    ISSN： 0385-8839

  259. Behavior of Cavitation Vibrations around A Typical Butterfly Valve of Offset-Leaf Type Peer-reviewed

    R. Oba, H. Soyama, K. Tani, S. Takeda, J. Higuchi, Y. Hirata

    Turbomachinery　24　(4)　193-199　1996/04

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.24.193 　

    ISSN： 0385-8839

  260. Methods for Estimating the Rate of Severe Cavitation Erosion Arising in a High-Specific-Speed Centrifugal Pump Peer-reviewed

    H. Soyama, S-R. Li, M. Tonosaki, K. Uranishi, H. Kato, R. Oba

    Trans. JSME(B)　62　(595)　841-846　1996/03

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.62.841 　

    ISSN： 0387-5016

    More details Close

    In order to find useful methods for estimating the rate of severe cavitation erosion arising in a typical centrifugal pump at high specific speeds such as Ns=300(m, m3/min, rpm), systematic erosion tests are carried out under various test conditions using three-dimensional impellers made of aluminum alloy. The following three effective and simple methods for estimating the erosion rate are presented. (i)Observation of the initial aspects of the eroded surface, (ii)Analysis of the intensity of the vibrating accelerations, and(iii)Examination of the relationship between the erosion rate and the position of maximum erosion rate.

  261. High-Speed Stereo-Observations of Highly Erosive Cavitating Flow-Pattern around A Typical Butterfly Valve of Offset-Leaf-Type Peer-reviewed

    R. Oba, H. Soyama, M. Iwasaki, S. Takeda, Y. Hirata, J. Higuchi

    Turbomachinery　24　(3)　129-135　1996/03

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.24.129 　

    ISSN： 0385-8839

  262. Cavitating Jets - Similarity Correlations Peer-reviewed

    H. Soyama, A. Lichtarowicz

    J. Jet Flow Engng.　13　(2)　9-19　1996

  263. Marked Peening Effects by Highspeed Submerged-Water-Jets -Residual Stress Change on SUS304- Peer-reviewed

    H. Soyama, Y. Yamauchi, T. Ikohagi, R. Oba, K. Sato, T, Shindo, R. Oshima

    J. Jet Flow Engng.　13　(1)　25-32　1996

  264. Vortex Cavitation in a Submerged Jet Peer-reviewed

    H. Soyama, A. Lichtarowicz, T. Momma

    Proc. 1996 ASME Fluids Engineering Division Summer Meeting, July 7-11, 1996, San Diego, California　FED-236　415-422　1996

  265. Formation Process of Vortex Ring Cavitation in High-Speed Submerged Water Jets Peer-reviewed

    Y. Yamauchi, S. Kawano, H. Soyama, K. Sato, Y. Matsudaira, T. Ikohagi, R. Oba

    Trans. JSME(B)　62　(593)　72-78　1996/01

    DOI： 10.1299/kikaib.62.72 　

  266. High-Speed Observations of Severe Cavitation Erosion in a High-Specific-Speed Centrifugal Pump Peer-reviewed

    H. Soyama, S-R. Li, M. Tonosaki, K. Uranishi, H. Kato, R. Oba

    Trans. JSME(B)　61　(591)　3945-3951　1995/11

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.61.3945 　

    ISSN： 0387-5016

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    In order to clarify severe pump erosion practically, cavitation aspects are precisely measured at a specific speed Ns=300 (m, m3/min, rpm) under various test conditions, especially at low flow rates, through a clear-lucite front shroud of the test impeller and the lucite casing, by means of instantaneous photography and a high-speed video camera, the maximum framing rate of which is 40500 frames per second. Erosion tests are also carried out using three-dimensional impellers made of aluminum alloy. Severe erosion takes place on several parts of the test impeller, i.e., on the main shroud and on the suction side. At a low flow rate, severe erosion occurs on the pressure side near the leading edge. This results from a vortex cavitation arising in the reverse flow region near the pump inlet.

  267. Behavior of Severe Cavitation Erosion Occurring in a High-Specific-Speed Centrifugal Pump due to Vibrations and Noise Peer-reviewed

    H. Soyama, S. Li, M. Tonosaki, K. Uranishi, H. Kato, R. Oba

    Trans. JSME (B)　61　(589)　3276-3281　1995/09

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.61.3276 　

    ISSN： 0387-5016

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    In order to study the behavior of severe cavitation erosion occurring in a typical centrifugal pump with a high specific speed of Ns = 300 (m, m3/min, rpm), the high-frequency vibrations and noises due to such cavitation erosion are systematically investigated under various test conditions. The present erosion tests are carried out using three-dimensional impellers made of aluminum alloy. In a field where the flow rates as well as NPSH are low, the vibrating accelerations and the acoustic power sharply increase, so that severe erosion takes place in this field. A large difference in flow pattern is clearly observed with respect to the flow rate.

  268. Visualization of Vortex-and Cloud-Cavitation around a Submerged Water-Jet by Stereoscopic Stacking Display of Digital Images

    H. Soyama, T. Ikohagi, R. Oba

    Flow Visualization and Image Processing of Multiphase System　FED-209　43-48　1995/08

  269. Suitable Waiting Operation of an MC-Centrifugal-Slurry- Pump

    S. Li, H. Soyama, T. Ikohagi, R. Oba, T. Ito

    Cavitation and Gas-Liquid Flow in Fluid Machinery and Devices　FED-226　143-149　1995/08

  270. High-Speed Observations of Highly Erosive Vortex Cavitation Using Image Processing Peer-reviewed

    K. Ohba, H. Soyama, S. Takeda, H. Inooka, R. Oba

    Journal of Flow Visualization and Image Processing　2　161-172　1995/07

  271. Singular Behavior of Severe Erosive Vortex Cavitation (Local Flow Velocity Distribution around a Bubble) Peer-reviewed

    H. Soyama, K. Ohba, T. Ikohagi, R. Oba

    Turbomachinery　23　(6)　315-318　1995/06

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.23.315 　

    ISSN： 0385-8839

  272. BASE-VENTED PERFORMANCE SIMULATION FOR SUPERCAVITATING HYDROFOILS WITH PSEUDO-KIRCHHOFF NOSES OPERATING WITHIN THE SUBCAVITATING REGION Peer-reviewed

    M OHYAMA, J ABE, Y SUNAYAMA, H SOYAMA, M YAMABE, R OBA

    JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING　38　(2)　258-264　1995/05

    ISSN： 0914-8817

  273. HIGH-SPEED OBSERVATIONS OF THE CAVITATION CLOUD AROUND A HIGH-SPEED SUBMERGED WATER-JET Peer-reviewed

    H SOYAMA, Y YAMAUCHI, Y ADACHI, K SATO, T SHINDO, R OBA

    JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING　38　(2)　245-251　1995/05

    ISSN： 1340-8054

  274. Vibrations and Noises Associated with Severe Cavitation Erosion Arisen in a High-Specific-Speed Centrifugal-Pump Peer-reviewed

    H. Soyama, R. Oba, K. Uranishi, H. Kato

    Proceedings of the International Symposium on Cavitation　225-232　1995/05

  275. A Suitable Degassing-Vacuum-Pressure and a Suitable Operation of the Medium Consistency MC-Centrifugal Slurry-Pump Peer-reviewed

    R. Oba, S. Li, T. Ito, S. Cao, H. Soyama, Y. Hirata, J. Higuchi

    Turbomachinery　23　(4)　207-211　1995/04

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.23.207 　

    ISSN： 0385-8839

  276. Ambient Pressure Effects upon Impinging Erosion Resulted by Highspeed Submerged Water-Jets

    Y. Yamauchi, H. Soyama, T. Ikohagi, R. Oba, K. Sato

    Proceedings of 4th Pacific Rim International Conference on Water Jet Technology　139-150　1995/04

  277. A New Peening Process by Means of Submerged Cavitating Water-Jets

    K. Sato, Y. Yamauchi, H. Soyama, T. Ikohagi, R. Oba, F. Manabe

    Proceedings of 4th Pacific Rim International Conference on Water Jet Technology　437　437-448　1995/04

  278. Unsteady Behavior of Cavitating Water Jet

    K. Takeya, H. Soyama, K. Sato, T. Ikohagi, R. Oba

    Proceedings of 4th Pacific Rim International Conference on Water Jet Technology　534-544　1995/04

  279. Marked Effects of Ambient Pressure on Impinging Erosion Induced by High-Speed Submerged Water Jets Peer-reviewed

    Y. Yamauchi, K. Asami, H. Soyama, K. Sato, T. Ikohagi, R. Oba

    Trans. JSME (B)　61　(583)　785-792　1995/03

    DOI： 10.1299/kikaib.61.785 　

  280. HIGH-SPEED STEREO-OBSERVATIONS OF VIOLENT VIBRATIONS ASSOCIATED WITH 3 TYPES OF CAVITATION Peer-reviewed

    H NAKA, H SOYAMA, K SAKAGAMI, R OBA, M YAMABE

    JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING　38　(1)　66-72　1995/02

    ISSN： 0914-8817

  281. SUITABLE REGION OF HIGH-SPEED SUBMERGED WATER JETS FOR CUTTING AND PEENING Peer-reviewed

    Y YAMAUCHI, H SOYAMA, Y ADACHI, K SATO, T SHINDO, R OBA, R OSHIMA, M YAMABE

    JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING　38　(1)　31-38　1995/02

    ISSN： 1340-8054

  282. High-speed observations of the cavitation cloud around a high-speed submerged water jet

    Hitoshi Soyama, Yoshiaki Yamauchi, Yasunori Adachi, Kazunori Sato, Takenori Shindo, Risaburo Oba

    JSME International Journal, Series B: Fluids and Thermal Engineering　38　(2)　245-251　1995

    Publisher: JSME

    DOI： 10.1299/jsmeb.38.245 　

    ISSN： 0914-8817

  283. Remarkable Effects of Leading and Trailing Edge Shapes upon Violent Vibrations of Supercavitating Hydrofoils Peer-reviewed

    H. Soyama, H. Naka, J. Abe, T. Miyakawa, M. Takahashi, T. Ikohagi, R. Oba

    Turbomachinery　22　(10)　596-600　1994/10

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.22.596 　

    ISSN： 0385-8839

  284. Vibrations on Typical Supercavitating Hydrofoils with Several Leading Edge Shapes Peer-reviewed

    H. Soyama, T. Ikohagi, R. Oba, H. Naka, T. Miyakawa, H. Kuwako

    Turbomachinery　22　(9)　533-539　1994/09

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.22.533 　

    ISSN： 0385-8839

  285. Development of Erosion in Highspeed Submerged-Water- Jets Peer-reviewed

    Y. Yamauchi, H. Soyama, K. Sato, T. Ikohagi, R.Oba

    Proceedings of 17th IAHR Symposium　2　687-697　1994/09

  286. Development Process of Severely Erosive Cavitation Peer-reviewed

    R. Oba, H. Soyama, Y. Ito, T. Ichioka

    Proceedings of 17th IAHR Symposium　567-578　1994/09

  287. Observations of Cavitation Associated with Severe Erosion in a Centrifugal Pump, Especially at a Low Flow Rate Peer-reviewed

    H. Soyama, K. Uranishi, M. Tonosaki, H. Kato, R. Oba

    Proceedings of 17th IAHR Symposium　579-590　1994/09

  288. Jet Structure Analyses on High-Speed Submerged Water Jets through Cavitation Noises Peer-reviewed

    Y. Adachi, H. Soyama, Y. Yamauchi, K. Sato, T. Ikohagi, R. Oba

    Trans. JSME (B)　60　(576)　2665-2670　1994/08

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.60.2665 　

    ISSN： 0387-5016

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    In order to establish a useful monitoring method for predicting the erosion induced by high-speed submerged water jets, we attempt to clarify the relation between the jet-structure and the cavitation noise arising around the free jets, by using two hydrophones, and also analyze the AE characteristics of the impulsive pressures induced by cavitation on the specimen of the impinging jets. It is found that the energies of high-frequency components in the jets change markedly with the injection pressure and the standoff distance. It is found that the AE characteristics are closely related to the impinging erosion.

  289. Curvature Effects upon Peening Action on Working Surfaces by Impinging High-Speed Submerged Waterjets Peer-reviewed

    Y. Yamauchi, H. Soyama, Y. Adachi, K. Sato, R. Oba

    Trans. JSME (B)　60　(576)　2671-2677　1994/08

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.60.2671 　

    ISSN： 0387-5016

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    In order to clarify curvature effects upon the peening action on a working surface resuling from impinging high-speed submerged waterjets, we systematically investigate the spatial distributions of the impulsive pressures induced by cavitation for several convex- and concave-cylindrical surfaces with various curvatures, by means of a pressure, sensitive film technique which can detect the spatial distributions easily. The distributions do not appreciably change with the curvature, except for the case when the cylinder diameter is less than the jetwidth. Expectedly, the impulsive pressures develop almost uniformly as far as the rear convex surface, even for a slender cylinder.

  290. High-Speed Observations of Highly Erosive Vortex Cavitation Using Image Processing Peer-reviewed

    K. Oba, H. Soyama, S. Takeda, H. Inooka, R. Oba

    Journal of the Visualization Society of Japan　14　(54)　179-184　1994/07

    Publisher: The Visualization Society of Japan

    DOI： 10.3154/jvs.14.179 　

    ISSN： 0916-4731

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    In order to clarify the mechanism of the severe erosion mainly resulted by the singular vortex cavitation, we carefully try to observe the vortex cavitation associated with the erosion around a butterfly valve by means of a high-speed video-camera, whose maximum framing rate is 40, 500 per seconds. The velocity of cavitating flow are measured with the correlation method, one of the digital-image processing-technique. It is worth noticing that the vortex cavitation develops in the boundary region between the main flow region, i. e., the orifice-jet, and the recirculating region. The cavitating vortex core consists of several tiny vortex cavitation. And the rotating velocity of the highly erosive vortex cavitation can be also detected by the technique.

  291. Cavitation Characteristics of Ultrapure Water (Behavior of Cavitation Nuclei in Vibratory Erosion Test) Peer-reviewed

    H. Soyama

    Trans. JSME (B)　60　(573)　1526-1531　1994/05

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.60.1526 　

    ISSN： 0387-5016

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    In order to establish the necessary conditions for cavitation tests using ultrapure water, relative air content rates, cavitation noises and bubbles rising from a vibratory cavitation test apparatus are carefully measured with respect to time. The bubble diameters are measured by the ascending velocities of the bubbles using an LDV. It is note worthy that the relative air content rates of ultrapure water are considerably scattered and the bubbles induced by vibration are smaller than those of tap and still water. The bubble sizes are comparable to the size of cavitation nuclei. The cavitation noises are always changing with time, especially the number of high amplitude acoustic pulses, however, there is no effect on water quality in the changes with time.

  292. High-Speed Observations of Highly Erosive Vortex Cavitation around Butterfly Valve Peer-reviewed

    H. Soyama, K. Ohba, S. Takeda, R. Oba

    Trans. JSME (B)　60　(572)　1133-1138　1994/04

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.60.1133 　

    ISSN： 0387-5016

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    In order to clarify the mechanism of the severe erosion mainly resulting from the singular vortex cavitation, we carefully observe the vortex cavitation associated with the erosion around a butterfly valve by means of a high-speed video camera, whose framing rate is 40500 per second. The velocity of cavitating flow is measured by the digital-image processing technique. It is worth noting that the vortex cavitation develops in the boundary region between the main flow region, i. e., the orifice-jet, and the recirculating region. The cavitating vortex core consists of several tiny vortex cavitations. The rotating velocity of the highly erosive vortex cavitation can also be determined by this technique.

  293. A Study of Unsteady Behavior on High-Speed Submerged Water Jets by Stereoscopic Stacking Display of Digital Images

    SOYAMA Hitoshi, IKOHAGI Toshiaki, OBA Risaburo

    Transactions of Visualization Society of Japan　14　(1)　123-126　1994

    Publisher: The Visualization Society of Japan

    DOI： 10.3154/jvs.14.Supplement1_123 　

    ISSN： 0916-4731

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    Recently, submerged water-jets are very often applied for cutting, peening and cleaning. In such a jet-working-capacity, the shedding of cavitation clouds and the vortex cavitation around the jets are the most important factor. In order to clarify the mechanism of the shedding around the jets, we systematically observe the aspects of the jets, by means of a highspeed-video-camera, whose maximum framing rate is 40500 per second, by using a laser-light-sheets. And the digital images taken by the video camera are stacked to a stereoscopic display to examine the jets behavior changing with time. The cavitation clouds and the vortex cavitation are stereoscopically displayed by the digital image-processing-technique.

  294. Observations of the Cavitating Jet in a Narrow Watercourse Peer-reviewed

    H. Soyama, T. Ikohagi, R. Oba

    Proc. 1994 (29th) Cavitation and Multiphase-Flow Forum (eds. O. Furuya and J. Katz, ASME, 1994)　FED-194　79-82　1994

  295. Numerical Simulations of Fluctuating Vortex around a Hydrofoil in Steady Inflow Peer-reviewed

    Hitoshi Soyama, Makoto Ohyama, Junpei Abe, Yoshihiko Sunayama, Masahiro Yamabe, Risaburo Oba

    Transactions of the Japan Society of Mechanical Engineers Series B　60　(570)　446-451　1994

    DOI： 10.1299/kikaib.60.446 　

    ISSN： 0387-5016

  296. Cavitation Noise Characteristics around High-Speed Submerged Water Jets Peer-reviewed

    Yasunori Adachi, Hitoshi Soyama, Yoshiaki Yamauchi, Kazunori Sato, Toshiaki Ikohagi, Risaburo Oba

    Transactions of the Japan Society of Mechanical Engineers Series B　60　(571)　730-735　1994

    DOI： 10.1299/kikaib.60.730 　

    ISSN： 0387-5016

  297. Development of Erosion in High-Speed Submerged Water Jets Peer-reviewed

    Yoshiaki Yamauchi, Hitoshi Soyama, Kazunori Sato, Toshiaki Ikohagi, Risaburo Oba

    Transactions of the Japan Society of Mechanical Engineers Series B　60　(571)　736-743　1994

    DOI： 10.1299/kikaib.60.736 　

    ISSN： 0387-5016

  298. Unsteady Behavior on High-Speed Submerged Water-Jets and Mechanism of Impinging Erosion Peer-reviewed

    Yoshiaki Yamauchi, Hitoshi Soyama, Kazunori Sato, Toshiaki Ikohagi, Risaburo Oba

    Transactions of the Japan Society of Mechanical Engineers Series B　60　(577)　2955-2960　1994

    DOI： 10.1299/kikaib.60.2955 　

    ISSN： 0387-5016

  299. High-Speed Observation of Ultra High-Speed Cavitating Submerged Water Jets Peer-reviewed

    H. Soyama, Y. Yamauchi, K. Sato, T. Ikohagi, R. Oba, R. Oshima

    Trans. JSME (B)　59　(568)　3714-3719　1993/12

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.59.3714 　

    ISSN： 0387-5016

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    This paper aims to clarify peculiar phenomena arising around a ultra high-speed submerged water jet accompanied by very severe cavitation. By means of a flow visualization technique with a xenon flash light, three kinds of water jets are carefully observed, and the spatial distributions of cavitation-pressure pulses around the jets are also measured with pressure-sensitive film. The effects of the working pressure and the shape of nozzles are clarified systematically. Thus, the characteristics and the structures of ultra high-speed cavitating submerged water jets are clearly shown.

  300. MARKED CHANGE IN SUBCAVITATION CASCADE PERFORMANCE RESULTING FROM A VERY SLIGHT MODIFICATION IN LEADING EDGES Peer-reviewed

    H SOYAMA, T NARASAKA, R OBA, R OSHIMA, J SATOH, S TANABE, K SHIMMEI

    JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING　36　(4)　524-531　1993/11

    ISSN： 1340-8054

  301. Numerical Simulations of Fluctuating Vortical Flows around a Hydrofoil Operating in the Steady Flow

    H. Soyama, M. Ohyama, J. Abe, Y. Sunayama, M. Yamabe, R. Oba

    Proceedings of 5th International Symposium on Computational Fluid Dynamics　3　144-149　1993/08

  302. Base-Vented Performance Simulation for Supercavitating Hydrofoils with Pseudo-Kirchhoff Nose Operating within the Subcavitating Region Peer-reviewed

    M. Ohyama, J. Abe, Y. Sunayama, H. Soyama, M. Yamabe, R. Oba

    Trans. JSME (B)　59　(562)　1913-1918　1993/06

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.59.1913 　

    ISSN： 0387-5016

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    In order to clarify supercavitating hydrofoil performance numerically, especially in the base-vented state at a low incidence, we try to make numerical simulations for three typical thin super cavitating hydrofoils with pseudo-Kirchhoff noses by means of the QUICK method. The precise water-tunnel tests on the supercavitating steady lift- and drag-performance for the foils are examined, after the marked effects of leading edge and the peculiar behavior of disc drag have been clarified. We find that the analyses agree well with the experiments, especially in the base-vented flow at low incidences, showing several interesting facts.

  303. High-Speed Observations of the Cavitation Cloud around a High-Speed Submerged Water-Jet Peer-reviewed

    H. Soyama, Y. Yamauchi, Y. Adachi, K. Sato, T. Shindo, R. Oba

    Trans. JSME (B)　59　(562)　1919-1924　1993/06

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.59.1919 　

    ISSN： 0387-5016

    More details Close

    In this paper, we attempt to clarify the jet structure and the behavior of severely erosive cavitation clouds around a high-speed submerged water-jet, using a high-speed movie camera with a framing rate of ten thousand frames. The effects of the injection pressure and the nozzle geometry on cavitation are also investigated. The experiments are performed with both a free jet and an impinging jet. It is clearly found that the cavitation clouds are periodically discharged. The cavitation clouds are also closely related to downstream instability and to the impinging erosion.

  304. High-Speed Observations of Highly erosive Vortex- Cavitation Arisen in a Centrifugal Pump Peer-reviewed

    H. Soyama, Y. Ito, S. Cao, R. Oba

    Turbomachinery　21　(4)　215-219　1993/04

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.21.215 　

    ISSN： 0385-8839

  305. Observations of Severely Erosive Vortex Cavitation in a Centrifugal Pump Peer-reviewed

    H. Soyama, T. Okamura, S. Saito, H. Kato, R. Oba

    Trans. JSME (B)　59　(560)　1140-1144　1993/04

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.59.1140 　

    ISSN： 0387-5016

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    In order to predict pump erosion practically, severe erosion is systematically and precisely observed in a typical centrifugal pump of specific speed Ns=150(m, m3/min, rpm) in various test conditions in relation to types of cavitation, by means of erosion-depth measurements, noise detections, and cavitation-pressure pulse measurements through the paint method as well as the pressure-sensitive film method. The severe erosion directly result from the vortex cavitation, and the erosion rates are closely related to the size and the occurrence frequency of the vortex cavitation.

  306. High-Speed Stereo-Observations of Violent Vibrations Associated with Three Types of Cavitation Peer-reviewed

    H. Naka, H. Soyama, K. Sakagami, R. Oba, M. Yamabe

    Trans. JSME (B)　59　(559)　691-695　1993/03

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.59.691 　

    ISSN： 0387-5016

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    To facilitate improvement of the reliability of hydraulic machinery, detailed behavior of the violent vibrations is systematically observed by means of high-speed stereophotography for the Eppler hydrofoil. We can clearly observe the following three types of violent vibrations : (i) those resulting on a single attached cavity at a larger incidence α_i, (ii) those resulting on large travelling bubbles at a small α_i, (iii) the mixed type.

  307. Behavior of the Erosion-Standoff-Distance Curves for High-Speed Water-Jets in Air Peer-reviewed

    H. Soyama, M. Shintani, T. Uchida, J. Higuchi, R. Oba

    Trans. JSME (B)　59　(559)　707-712　1993/03

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.59.707 　

    ISSN： 0387-5016

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    In order to clarify the mechanism of water-jet erosion, we systematically investigate the erosion-standoff-distance curves, the erosion-time curves, and detailed aspects of the eroded surface for two typical types of nozzles, i.e., conical and cylindrical nozzles. Clearly, the erosion-time curves are markedly different at the 1st peak, at the valley and at the 2nd peak. Hence, the mechanism of erosion is significantly changed with an increase in the standoff distance χ.

  308. High-Speed Observations of Highly Erosive Vortex Cavitation around a Butterfly Valve Peer-reviewed

    OHBA Kohtaro, SOYAMA Hitoshi, TAKEDA Sho, ISHIHARA Tadashi, INOOKA Hikaru, OBA Risaburo

    Transactions of Visualization Society of Japan　13　(2)　13-18　1993

    Publisher: The Visualization Society of Japan

    DOI： 10.3154/jvs.13.Supplement2_13 　

    ISSN： 0916-4731

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    In order to clarify the mechanism of the severe erosion mainly resulted by the singular vortex cavitation, we carefully try to observe the vortex cavitation associated with the erosion around a butterfly valve by means of a high-speed video-camera, whose framing rate is 40500 per seconds. The velocity of cavitating flow are measured by using the digital-image processing-technique. It is worth noticing that the vortex cavitation develops in the boundary region between the main flow region, i.e., the orifice-jet, and the recircurating region. The cavitating vortex core consists of several tiny vortex cavitation. And the rotating velocity of the highly erosive vortex cavitation can be also detected by the technique.

  309. The Suitable Region of High-Speed Submerged Water-Jets for Cutting and Peening Peer-reviewed

    Y. Yamauchi, H. Soyama, Y. Adachi, K. Sato, T. Shindo, R. Oba, M. Yamabe, R. Oshima

    Trans. JSME (B)　59　(557)　16-22　1993/01

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.59.16 　

    ISSN： 0387-5016

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    In order to establish techniques of cutting, drilling, peening and flushing by high-speed submerged water-jets, we systematically observe the eroded surface on aluminum-alloy test-pieces in relation to the aspects of cavitating jets, especially for the impinging jet through lucite-test-pieces, for several types of nozzles. The impulsive pressures induced by the impinging jets are also measured by means of pressure-sensitive film. It is concluded that the erosion characteristics are quite different in two regions differentiated by the standoff distance. Cylindrical, small and deep pits occur in one of the regions, while small lots of plastic deformations occur in the other region. The former is suitable for cutting, while the latter is for peening.

  310. Scaling Effects on Cavitation Erosion Pits Peer-reviewed

    H. Soyama

    Trans. JSME (B)　58　(555)　3366-3372　1992/11

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.58.3366 　

    ISSN： 0387-5016

    More details Close

    In order to clarify the scaling effects on cavitation erosion, erosion pits are carefully measured using a digital image processing technique for four similar flat-hydrofoils with chord length C from 53mm to 160mm, corresponding to the cavitation aspects, under similar conditions of cavitation-nuclei size-distribution in the test water, flow velocity, angle of attack and cavitation number. Because the cavitation intensity is correspond to types of cavitation and it is also associated with cavitation-nuclei size-distribution and flow velocity. The erosion intensity I_<ER>, that is defined by the diameter of erosion pits and the pitting rate, is determined to be a power law : I_<ER> ∝ C^n. In the average erosion intensity over the hydrofoils, the exponent n is 2, while at the maximum local erosion intensity, the exponent n is 4.5. The erosion pits predominantly result from the vortex cavitation.

  311. Behavior of Cavitation Nuclei in High-Speed Submerged- Water-Jet Tests Peer-reviewed

    Y. Yamauchi, H. Soyama, Y. Adachi, T. Ikohagi, R. Oba

    Trans. JSME (B)　58　(554)　2947-2952　1992/10

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.58.2947 　

    ISSN： 0387-5016

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    To elucidate clear the behavior of ambient-and inflow-cavitation-nuclei distributions associated with high-speed submerged water-jet tests, we systematically measured the distributions, and the change in them with time by means of a Coulter counter. These distributions are one of the most dominant parameters in all ambient and inflow types of cavitation. It was shown that our test facility is very suitable for high-speed submerged-water-jet tests, and it was also noted that the distributions varied in the test water with high-pressure treatment applied by a plunger pump.

  312. Marked Effects of Leading Edge upon Supercavitating Hydrofoil Performance Peer-reviewed

    J. Abe, H. Soyama, Y. Ito, H. Kuwako, R. Oba

    Proceedings of 16th IAHR Symposium　575　575-584　1992/09

  313. High-Specific-Speed Kaplan-Turbine-Cascade Whose Performance Scarecely Changes with Cavitation Number Peer-reviewed

    H. Soyama, T. Narasaka, R. Oba, R. Oshima, J. Satoh, S. Tanabe, K. Shimmei

    Trans. JSME (B)　58　(549)　1361-1366　1992/05

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.58.1361 　

    ISSN： 0387-5016

    More details Close

    In order to find low-drag thin hydorfoils in cascades applicable to Kaplan turbines, we systematically investigate the subcavitating perfomance and the cavitation aspects around circular-shape hydrofoils for two cascade arrangements of various cavitation numbers and incidences. Our previous paper showed that the separation bubble near the leading edge, especially a long bubble, markedly increases the drag for thin hydrofoils in the cascade of present interest. Hence we investigate the behavior of the long bubble here. We try to suppress the long bubble, so that there is a marked increase in drag, by applying accelerating cascade effects of high-cambered hydrofoils effectively. We find a superior cascade hydorfoil, whose perfomance scarcely changes with cavitation number.

  314. A Marked Change in Subcavitating-Cascade-Performance Resulted from a Very Small Modification in Leading Edges Peer-reviewed

    H. Soyama, T. Narasaka, R. Oba, R. Oshima, J. Satoh, S. Tanabe, K. Shimmei

    Trans. JSME (B)　58　(548)　1283-1288　1992/04

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.58.1283 　

    ISSN： 0387-5016

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    For the first step to find low-drag thin hydrofoils in cascade applicable to Kaplan-turbines, the subcavitating performance and the corresponding cavitation aspects for two different hydrofoils whose shapes are quite the same except the neighborhood of the leading edge within one percent chord. The leading edges are somewhat modified, for two cascade arrangements of a pitch-chordratio t/l=1.14 and of two cascade angles θ_1=23°and 35°, for various cavitation numbers and various incidences. Clearly, a marked change in drag is resulted from such a very small modification around the edge, which is closely related to the boundary layer separation around the leading edge. It is also suggested to the suitable modifications without separation bubble.

  315. Cavitation Observations of Severely Erosive Vortex Cavitation Arising in a Centrifugal Pump Peer-reviewed

    H. Soyama, H.Kato, R. Oba

    Proc. Institut. Mech. Eng., Cavitation, Int. Conf. (ed. E. Grist, Mech. Engng. Pub. Ltd., 1992, Suffolk)　103-110　1992

  316. A STUDY ON PEENING BY SUBMERGED ULTRA-HIGH-SPEED WATER-JETS Peer-reviewed

    K SATO, H SOYAMA, Y YAMAUCHI, T IKOHAGI, R OBA, R OSHIMA

    JET CUTTING TECHNOLOGY　13　413-424　1992

  317. SEM Observations on the Progress of Rapid Cavitation Erosion Arisen in a Typical Centrifugal Pump Peer-reviewed

    H. Soyama, Y. Ito, T. Ichioka, R. Oba, H. Kato

    Cavitation and Multiphase Flow Forum　FED-109　193-198　1991/07

  318. The Behavior of Cavitation in a Branch Duct under Pulsating Flow Peer-reviewed

    R. Ikeda, Y. Ito, Y. Shoji, H. Soyama

    Trans. JSME (B)　57　(537)　1530-1534　1991/05

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.57.1530 　

    ISSN： 0387-5016

    More details Close

    To clarify the capacity effect by cavitation bubbles, the cavitation aspects and the vibrational acceleration were studied experimentally in pulsating flows through a branch duct. When the pulsation is given on the upstream side, the wall pressure and the flow velocity fluctuate in phase, while when the pulsation is given on the downstream side, there is a phase difference of 900 between them. The incipient and the desinent cavitation number have approximately the same value. The characteristics of such pulsations are independent of the pulsating conditions and the types of cavitation.

  319. The Severe Erosion Monitoring by Detecting Cavitation Noise Peer-reviewed

    H. Soyama, K. Tani, R. Oba, Y. Ito, H. Kato

    Proc. Symp. Hydroacoustic Facilities, Instrumentation, and Experimental Techniques (eds. T.M. Farabee and R.E. Arndt, ASME, 1991)　NCA-10　37-41　1991

  320. Severe-Erosion-Progress in a Typical Centrifugal Pump (1st Report, Marked Effects of Upstream Cavitator) Peer-reviewed

    H. Soyama, Y. Ito, T. Ichioka, K. Uranishi, H. Kato, R. Oba

    Turbomachinery　18　(12)　691-698　1990/12

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.18.691 　

    ISSN： 0385-8839

  321. Severe-Erosion-Progress in a Typical Centrifugal Pump (2nd Report, SEM Observations of Eroded Surface) Peer-reviewed

    H. Soyama, Y. Ito, T. Ichioka, H. Kato, R. Oba

    Turbomachinery　18　(12)　699-707　1990/12

    Publisher: Turbomachinery Society of Japan

    DOI： 10.11458/tsj1973.18.699 　

    ISSN： 0385-8839

  322. Scaling Effects on Cavitation Noise Peer-reviewed

    H. Soyama, Y. Ito, R. Oba

    Proc. Int. Symp. on Cavitation Noise and Erosion in Fluid Systems (eds. R.E.A. Arndt, M.L. Billet and W.K. Blake, ASME, 1989)　FED-88　41-46　1989/12

  323. Subcavitating Performance of Hydrofoils in Accelerating Cascade Design for High-Specific-Speed Kaplan-Turbines (1st Report, Suitable Cascade Hydrofoils of 3 Percent in Thickness) Peer-reviewed

    T. Narasaka, R. Oba, H. Soyama, J. Satoh, Y. Wada, S. Tanabe

    Trans. JSME (B)　55　(519)　3397-3402　1989/11

    DOI： 10.1299/kikaib.55.3397 　

  324. A Study on Cavitation Scale Effects Especially with Respect to Cavitation-Induced High-Pressure Pulses Peer-reviewed

    Y. Ito, R. Oba, H. Soyama, H. Ogata, T. Okamura, S. Sudo, R. Ikeda

    Trans. JSME (B)　54　(506)　2727-2733　1988/10

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.54.2727 　

    ISSN： 0387-5016

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    As a first step to clarifying the mechanism of scale effects on cavitation erosion, cavitation-induced shock pressure pulses were carefully investigated around four similar flat hydrofoils, from 53mm to 160mm in a chord length C, under a so-called"true similar conditions"of the same flow velocity, incidence and cavitation number as well as almost the same nuclei distribution in the test water, within the subcavitation region. Under these similar conditions, no marked scale effects on the mean pressure are recognized. When C is large, very large U-shaped vortex cavitation bubbles grow and predominantly collapse, resulting in very high locally concentrated pressure pulses on the foil surface. On the other hand, a large number of moderate pressure pulses attack the surface in a smaller C.

  325. Abrupt Cavity Separation on Cavitating Hydrofoils Peer-reviewed

    Y. Ito, R. Oba, H. Soyama, T. Narasaka, R. Oshima

    Trans. JSME (B)　54　(503)　1555-1559　1988/07

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/kikaib.54.1555 　

    ISSN： 0387-5016

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    To improve the physical understanding of the fatal "violent vibration" in the near-transition range, the "abrupt cavity separations" associated with the vibration were precisely observed in a water flow around two-dimensional hydrofoils, for various angles of incidence and cavitation numbers, by means of high-speed photography. The cavity separation is a periodic phenomenon that the subcavitating cavity and the supercavitating cavity form alternatively between several spanwise locations, accompanied with a bubble cloud shedding from the subcavitation cavity. The cavity separation line becomes highly distorted immediately after the shedding.

Show all ︎Show first 5

Misc. 257

  1. Laser Cavitation Peening for Improvement of Fatigue Properties of Metallic Materials International-journal Invited

    Hitoshi Soyama

    Metal Finishing News　25　(5)　56-59　2024/09

    Publisher: Metal Finishing News

  2. Fundamentals and Applications of Cavitation Peening Invited Peer-reviewed

    Hitoshi Soyama

    JSSE Magazine　(633)　3-6　2024/09

    Publisher: 日本ばね学会

  3. 連載 ショットピーニングの原理・応用・未来〔6〕ショットレスピーニング２－キャビテーションピーニング－ Invited

    祖山均

    機械と工具　14　(7)　68-74　2024/07/10

  4. Development of Torsion Fatigue Tester to Evaluate Surface Modification Layer of 3D-Metal International-journal Invited

    Hitoshi Soyama, Chieko Kuji

    Metal Finishing News　24　(5)　52-55　2023/09

    Publisher: Metal Finishing News

  5. 東北大学大学院工学研究科ファインメカニクス専攻 材料メカニクス講座 知的計測評価学分野—Department of Finemechanics, Graduate School of Engineering, Tohoku University Intelligent Sensing of Materials, Materials Physics and Engineering

    祖山 均, 久慈 千栄子

    ターボ機械 = Turbomachinery　50　(12)　756-762　2022/12

    ISSN： 0385-8839

  6. Water Jet, Pulsed Laser and Ultrasonic Cavitation Peening: Comparison with Shot Peening International-journal International-coauthorship Invited

    Hitoshi Soyama, Alexander M. Korsunsky

    Metal Finishing News　23　(5)　54-56　2022/09

    Publisher: Metal Finishing News

  7. Creation of functional heat radiation surface by surface texturing

    KUJI Chieko, ISHII Masayuki, YOSHIKAWA Ryuichi, SOYAMA Hitoshi

    The Proceedings of the Materials and Mechanics Conference　2022　OS1802　2022

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemm.2022.os1802 　

    eISSN： 2424-2845

    More details Close

    Industrial interest in thermal management is rapidly increasing due to the increase in the amount of heat generated by semiconductor devices as their performance improves in terms of miniaturization, higher power output, and higher density. Radiation of heat from a material surface is a phenomenon of electromagnetic wave emission, and the wavelength of the emitted electromagnetic wave varies with temperature according to Planck's law. In this paper, we aim to create functional heat radiation surfaces that can enhance heat dissipation performance in a specific temperature range by controlling the wavelength range of electromagnetic waves emitted from the material surface. Micro-cutting and ultrashort pulsed laser machining were used to fabricate various microstructures and their effects on heat radiation were investigated. It was found that the combination of a groove structure with an electromagnetic wavelength size and a sub-micrometer size groove structure can provide a temperature selectivity that increases the radiation flow in a specific temperature range.

  8. Local crystallization investigation of amorphous alloys using a two-dimensional detector by X-ray diffraction method

    KUJI Chieko, SOYAMA Hitoshi

    The Proceedings of the Materials and Mechanics Conference　2022　OS0502　2022

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemm.2022.os0502 　

    eISSN： 2424-2845

    More details Close

    Amorphous alloys without a crystalline structure exhibit excellent soft magnetic properties but are difficult to machine due to their tough mechanical properties. The authors have proposed a new machining method that improves machinability by crystallizing only the local regions involved in machining, thereby reducing local strength and toughness. To realize this method, it is necessary to evaluate the crystallinity of the local area nondestructively, but it is difficult to detect a local area of crystals precipitated in amorphous materials by the conventional X-ray diffraction method (sin2ψ method). In this paper, we attempted to investigate the crystallinity of the local area using a two-dimensional X-ray diffraction method (2D method) with a two-dimensional detector. Fe-based amorphous alloys were locally crystallized using an ultrashort pulsed laser with a beam diameter of about 66 μm. Then, it was revealed that the 2D method can evaluate even a small area of crystallization within several tens of micrometers.

  9. Proposal of Evaluation Method of Elastic and Plastic Properties of Mechanical Surface Modified Layer of Metallic Materials by Indentation Test

    SOYAMA Hitoshi, KUJI Chieko

    The Proceedings of the Materials and Mechanics Conference　2022　OS0517　2022

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemm.2022.os0517 　

    eISSN： 2424-2845

    More details Close

    In order to improve fatigue properties of metallic materials, mechanical surface modification such as shot peening is one of powerful methods. Major key parameters of the material properties on the improvement are work hardening and introduction of compressive residual stress. In the case of measurement by using an indentation test, hardness which relates resistance on plasticity such as yield stress is evaluated, and residual stress is also affected by residual stress. Namely, elastic properties such as compressive residual stress can be measured by the indention test as well as material flow stress characteristic of the transition from elastic to plastic deformation. In the present paper, an evaluation method of elastic and plastic properties of mechanical surface modified layer by the indentation test was proposed. In view point of practical application, as the indentation test which was similar to Rockwell superficial hardness was useful, the ratio of preliminary minor load and additional major load was investigated.

  10. R&D on Mercury Target for Spallation Neutron Source to Improve the Durability under High Power Operation (1) Mechanism of Damage Mitigation Effects by Gas Bubbles and Damage Observation Results

    粉川広行, 川島広之, 有吉玄, 涌井隆, 猿田晃一, 直江崇, 羽賀勝洋, 二川正敏, 祖山均, 久慈千栄子, 伊藤啓, 田中伸厚

    日本原子力学会秋の大会予稿集(CD-ROM)　2022　2022

  11. R&D on Mercury Target for Spallation Neutron Source to Improve the Durability under High Power Operation (2) Dominant factors in local impact forces caused by bubble collapse

    川島広之, 粉川広行, 二川正敏, 祖山均, 久慈千栄子, 田中伸厚

    日本原子力学会秋の大会予稿集(CD-ROM)　2022　2022

  12. Surface Treatment by Using Cavitation Peening Invited Peer-reviewed

    Hitoshi Soyama

    Journal of Japanese Society of Tribologists　66　(12)　912-918　2021/12

    Publisher: Japanese Society of Tribologists

    More details Close

    Cavitation is harmful phenomenon for hydraulic machineries such as pumps and valves, as cavitation normally causes severe impact at bubble collapse. However, cavitation impacts can be utilized for surface treatment to enhance fatigue strength and/or fretting fatigue of metallic materials in the same way of shot peening. The surface treatment using cavitation impact is named as “cavitation peening”. The great advantage of cavitation peening is that the increase of surface roughness caused by cavitation peening is lesser than that of shot peening, as shots are not used in cavitation peening. In typical case of cavitation peening, cavitation is caused by injecting a high-speed water jet in water and it is called as a cavitating jet. Cavitation can be generated by irradiating a laser pulse in water. In the present paper, mechanism of cavitation peening using the cavitating jet and the submerged pulse laser is explained, and the effect of cavitation peening on the fatigue properties is revealed.

  13. Improvement of Fatigue Properties of Magnesium Alloy by Cavitation Peening Using a Submerged Water Jet and a Pulse Laser International-journal Invited

    Hitoshi Soyama

    Metal Finishing News　22　(5)　54-57　2021/09

    Publisher: MFN International

  14. Revision of Material Testing Using a Cavitating Jet ASTM G134 Invited Peer-reviewed

    Hitoshi Soyama

    Turbomachinery　49　(2)　65-72　2021/02/10

    Publisher: Turbomachinery Society of Japan

  15. Cavitation Abrasive Surface Finishing (CASF) for the Improvement of Fatigue Strength of Titanium Alloy Ti6Al4V Manufactured by Electron Beam Melting International-journal International-coauthorship Invited

    Hitoshi Soyama, Daniel G. Sanders

    Metal Finishing News　21　(5)　56-58　2020/09

    Publisher: MFN International

  16. Development of Cavitation Generator Mimicing Pistol Shrimp

    SOYAMA Hitoshi, TANAKA Mayu, TAKIGUCHI Takashi, YAMAMOTO Matuso

    The Proceedings of Conference of Tohoku Branch　2020.55　111_paper　2020

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmeth.2020.55.111_paper 　

    eISSN： 2424-2713

  17. Cavitation Erosion of Titanium Alloy Ti-6Al-4V Manufactured by 3D Additive Manufacturing

    SASAKI Hirotoshi, SOYAMA Hitoshi

    The Proceedings of Conference of Tohoku Branch　2020　(0)　162_paper　2020

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmeth.2020.55.162_paper 　

  18. Comparison of Shot peening, Cavitation Peening and Submerged Laser Peening on Improvement of Fatigue Strength of Additive Manufactured Metal Invited

    Hitoshi SOYAMA

    Metal Finishing News　20　(5)　56-58　2019/09

  19. キャビテーション噴流による口腔バイオフィルム除去

    山田純輝, 滝口尚, 祖山均, 山本松男

    砥粒加工学会学術講演会講演論文集(CD-ROM)　2019　2019

  20. Comparison of Various XRD Methods on Evaluation of Residual Stress Introduced by Submerged Laser Peening Invited

    Hitoshi SOYAMA

    Metal Finishing News　19　(5)　54-57　2018/09

  21. Aiming at Improvement of Peri-Implantitis Invited

    YAMADA Junki, TAKIGUCHI Takashi, SOYAMA Hitoshi, YAMAMOTO Matsuo

    the Quintessence　37　(7)　1484-1485　2018/07

    ISSN： 0286-407X

  22. Overview of Cavitation Peening and its Practical Application for Mechanical Materials and Components Invited

    SOYAMA Hitoshi

    MECHANICAL SURFACE TECH　(44)　29-31　2018/06

  23. Cleaning by Using a Cavitating Jet Invited

    SOYAMA Hitoshi

    Industrial Cleaning　(21)　23-29　2018/04

  24. 水中レーザピーニングの加工能力における気泡径の影響

    佐々木裕章, 伊賀由佳, 祖山均

    第19回キャビテーションに関するシンポジウム, 札幌(2018.10.18-19(19)), No. 25　2018

  25. Cavitation Process Invited

    SOYAMA Hitoshi

    Abrasive Technology　61　(12)　643-646　2017/12

  26. Key Factors on Cavitation Peening Invited

    SOYAMA Hitoshi

    Metal Finishing News　18　(4)　56-58　2017/07

  27. Recent research on cavitation peening

    祖山均

    ふぇらむ　22　(4)　176-180　2017/04/01

    Publisher: 日本鉄鋼協会

    ISSN： 1341-688X

  28. Experimental verification of the hydrogen concentration around a crack tip using spot X-ray diffraction

    O. Takakuwa, T. Fujisawa, H. Soyama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY　41　(48)　23188-23195　2016/12

    DOI： 10.1016/j.ijhydene.2016.10.083 　

    ISSN： 0360-3199

    eISSN： 1879-3487

  29. Mechanical Surface Treatment of Duralumin by Laser Abrasion and Laser Cavitation

    Hitoshi Soyama

    Metal Finishing News　17　(4)　56-59　2016/07/01

  30. 1203 Fundamental Study on Erosion by a Cavitating Jet in Water : Influence of Nozzle Outlet Geometry

    KASAHARA Soichiro, OKADA Takashi, YAMAMOTO Kohei, SEKI Masanori, SOYAMA Hitoshi

    2016　(54)　"1203-1"-"1203-2"　2016/02/26

    Publisher: The Japan Society of Mechanical Engineers

  31. 133 Similarity between Cavitation Bubble Produced by Pistol Shrimp and Bubble Induced by Pulse Laser

    SOYAMA Hitoshi

    2016　(51)　63-64　2016

    Publisher: The Japan Society of Mechanical Engineers

  32. 流動キャビテーションの洗浄および化学反応への有効利用

    祖山 均

    Chemical Engineering　61　(1)　24-30　2016/01/01

    Publisher: 化学工業社

    ISSN： 0387-1037

  33. 203 Evaluation of Mechanical Properties of Biomineral by Means of Micro-Indentation Test

    HOSHINO Junki, MATSUDA Kyuhei, TAKAKUWA Osamu, SOYAMA Hitoshi

    2015　(51)　"203-1"-"203-2"　2015/09/26

    Publisher: The Japan Society of Mechanical Engineers

  34. J0320103 Evaluation of the Hydrogen Concentration Behaviour around a Crack Tip by Means of Micro Area X-ray Diffraction Measurement

    TAKAKUWA Osamu, Fujisawa Takuya, SOYAMA Hitoshi

    Mechanical Engineering Congress, Japan　2015　"J0320103-1"-"J0320103-3"　2015/09/13

    Publisher: The Japan Society of Mechanical Engineers

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    Here the present paper proposes a method employing micro-area X-ray diffraction analysis to evaluate local hydrogen concentration behavior. Hydrogen concentrating around a crack tip significantly accelerates crack propagation in metals, i.e., hydrogen embrittlement. The concentration behavior of hydrogen has not been revealed yet. In order to solve mechanism of hydrogen embrittlement, hydrogen concentration behavior in local area, e.g., a crack tip, has to be cleared by not only a numerical analysis but also an experimental approach. The present study takes notice of hydrogen-induced lattice strain and X-ray diffraction was employed to detect variation of lattice spacing before and after hydrogen charging. Here we demonstrate using X-ray diffraction applied to a micro area that hydrogen concentrates around an elastic-plastic boundary at vicinity of a crack.

  35. G0300901 Mechanical Surface Treatment of Duralumin by Laser Cavitation

    SOYAMA Hitoshi, UENO Yuko

    Mechanical Engineering Congress, Japan　2015　"G0300901-1"-"G0300901-3"　2015/09/13

    Publisher: The Japan Society of Mechanical Engineers

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    Pulse laser produces two kinds of shock wave related to laser abrasion and bubble collapse. In the case of laser peening, the shock wave induced by laser abrasion in water was normally used. However, the shock wave induced bubble collapse can be also used for the mechanical surface treatment. In the present paper, it was revealed that the noise corresponding to the shock wave by bubble collapse produced by pulse laser was stronger than that of laser abrasion and we demonstrated that the pulse laser at the present condition can be applied for the mechanical surface treatment.

  36. 機械工学年鑑，7. 流体工学

    西山秀哉, 福西祐, 伊澤精一郎, 浅井圭介, 澤田恵介, 孫明宇, 祖山均, 石本淳, 山本悟, 伊賀由佳, 須藤誠一, 中野政身, 佐藤岳彦, 高奈秀匡, 徳増崇, 米村茂, 早瀬敏幸, 石川拓司

    日本機械学会誌　118　(1161)　27-33　2015/08/05

    Publisher: 日本機械学会

  37. Basis for Classification between Cavitation Peening and Water Jet Peening Invited

    Hitoshi Soyama

    Metal Finishing News　16　(4)　58-60　2015/07

  38. 305 Effect of Surface Properties on Fatigue Life of Cavitation-Peened Steel Roller

    NAGAHASHI Yuta, SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro

    2015　(53)　"305-1"-"305-2"　2015/02/27

    Publisher: The Japan Society of Mechanical Engineers

  39. Evaluation of Yield Stress of Mechanical Surface Modified Duralumin by Inverse Analysis

    UENO Yuko, SOYAMA Hitoshi

    The Computational Mechanics Conference　2014　(27)　867-869　2014/11/22

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-026X

  40. B-24 Evaluation of Fluctuation of Knee by Detecting Position of Knee and Thigh

    SOYAMA Hitoshi

    Symposium on sports and human dynamics　2014　"B-24-1"-"B-24-5"　2014/10/29

    Publisher: The Japan Society of Mechanical Engineers

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    In order to reduce risk of gonalgia at middle age and iliotibial band syndrome, i.e. IT band syndrome, which is called as runner's knee, biomechanics movement of knee at running and jogging is key point. Too big fluctuation in the perpendicular to the running direction might be a source of gonalgia. When a runner can recognize proper movement at running by himself, the risk of runner's knee might be reduced. In the present paper, in order to recognize the proper movement of knee, an evaluation method of the fluctuation of knee was proposed. The movement of knee was evaluated by detecting difference between knee and thigh using a high speed video camera and pattern recognition of image processing. In order to investigate a possibility of reducing method by sole insert, the fluctuation of the knee was measured changing with shoe and sole insert. It was concluded that the fluctuation of the knee could be measured by a high speed video camera and image processing.

  41. G0410204 Durability of a spinal fixation device made of a low Young's modulus titanium alloy subjected to surface hardening

    NARITA Kengo, NIINOMI Mitsuo, NAKAI Masaaki, SUYALATU, SOYAMA Hisashi, TAKAKUWA Osamu

    Mechanical Engineering Congress, Japan　2014　"G0410204-1"-"G0410204-2"　2014/09/07

    Publisher: The Japan Society of Mechanical Engineers

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    Ti-29Nb-l3Ta-4.6Zr alloy (TNTZ) is expected to be used as biomedical applications such as a spinal fixation device. For a practical application, high durability of the spinal fixation device is required in order to ensure mechanical safety. The durability of the spinal fixation device with a rod made of TNTZ subjected to a surface hardening treatment was investigated in this study. The rod was prepared through a levitation melting, a hot-forging at 1273K, a solution treatment at 1063K for 3.6 ks subsequently water quenching, machining and finally a cavitation peening (CP) treatment for surface hardening (TNTZ-CP rod). Microstructure was observed using transmission electron microscopy (TEM). The durability was evaluated by compressive fatigue test applied to the spinal fixation device. Nano-scale graines were observed at the surface of the TNTZ-CP rod. The nanocrystalization was caused by the CP treatment. The compressive fatigue strength of the spinal fixation device with the TNTZ-CP rod was higher than that of spinal fixation device with a non-CP treated TNTZ rod.

  42. 313 Effect of Hydrogen on the Indentation Deformation in Grain and Grain Boundary of Stainless Steel

    MANO Yuta, TAKAKUWA Osamu, SOYAMA Hitoshi

    2014　(50)　61-62　2014/09/05

    Publisher: The Japan Society of Mechanical Engineers

  43. 111 Improvement of Fatigue Strength of Duralumin Plates with an Open Hole by Re-circulating Shot Peening Method Using a Water Jet

    UENO Yuko, SOYAMA Hitoshi

    2014　(50)　1-2　2014/09/05

    Publisher: The Japan Society of Mechanical Engineers

  44. 122 Proposal of a Method to Evaluate Local Hydrogen Content of Stainless Steel by Stress Measurement

    TAKAKUWA Osamu, FUJISAWA Takuya, SOYAMA Hitoshi

    2014　(50)　15-16　2014/09/05

    Publisher: The Japan Society of Mechanical Engineers

  45. OS1007 Effect of Surface Stress on the Hydrogen Invasion of Austenitic Stainless Steel and its Interaction

    TAKAKUWA Osamu, MANO Yuta, SOYAMA Hitoshi

    2014　"OS1007-1"-"OS1007-2"　2014/07/19

    Publisher: The Japan Society of Mechanical Engineers

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    In order to reveal the effect of surface stress on the invasion of austenitic stainless steel by hydrogen and its interaction, thermal desorption analysis and X-ray diffraction stress measurements were conducted on hydrogen charged specimens after surface finishing. The obtained results show tensile residual accelerated invasion by hydrogen by 2.7 times compared to the case of which compressive residual stress was introduced. In addition, the stress was varied due to the presence of hydrogen as a reactive stress was generated by base metal against increase in the volume. This reactive stress was defined as hydrogen-induced compressive stress. It had a close relation with hydrogen content.

  46. OS1006 Evaluation of the Local Hydrogen Invasion of Austenitic Stainless Steel by Means of an Indentation Test

    MANO Yuta, TAKAKUWA Osamu, SOYAMA Hitoshi

    2014　"OS1006-1"-"OS1006-3"　2014/07/19

    Publisher: The Japan Society of Mechanical Engineers

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    In order to investigate the relationship between hydrogen induced hardening of austenitic stainless steel and the hydrogen content, the spherical micro-indentation tests and thermal desorption analyses have been conducted on hydrogen charged austenitic stainless steel JIS SUS316L. Hydrogen has been charged by using cathodic method. In order to change the hydrogen content, current density and charging time are changed from 0.01 mA/mm^2 to 1.0 mA/mm^2, from 0 h to 48 h respectively. The obtained results show the hardness increase along with charging current density and charging time. Hydrogen content also depends on the charging current density and charging time. These relationships result in the linear correlation between hydrogen induced hardening of austenitic stainless steel and the hydrogen content. Hydrogen enhanced hardening might be due to dislocation-pinning effect of hydrogen. Thus there is a possibility to apply micro-indentation tests for measurements of hydrogen content.

  47. OS1005 Suppression of Hydrogen Embrittlement of Stainless Steel by Improving Residual Stress Using Cavitation Peening

    SOYAMA Hitoshi, TAKAKUWA Osamu

    2014　"OS1005-1"-"OS1005-2"　2014/07/19

    Publisher: The Japan Society of Mechanical Engineers

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    In order to realize sustainable society using hydrogen for main energy source, hydrogen embrittlement is big issue to be solved. As hydrogen embrittlement is accelerated near crack tip region where tensile stress exists, improvement of residual stress, i.e., change of residual stress from tension to compression, might suppress the hydrogen embrittlement. In the present paper, the crack propagation of stainless steel exposed to hydrogen was examined considering the residual stress on the surface. The tensile residual stress was introduced by an angle grinder, then the residual stress was improved by cavitation peening. Cavitation peening was a peening method in the same way as shot peening using cavitation impacts produced by a cavitating jet, i.e., a submerged water jet. It was revealed that the crack propagation rate of the specimen in which tensile residual stress was introduced and exposed to hydrogen was suppressed by improving residual stress using cavitation peening.

  48. OS1008 Suppression of Fatigue Crack Growth in Hydrogen-Charged SCM435 by Cavitation Peening

    KUMAGAI Naoki, TAKAKUWA Osamu, SOYAMA Hitoshi

    2014　"OS1008-1"-"OS1008-2"　2014/07/19

    Publisher: The Japan Society of Mechanical Engineers

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    In order to investigate suppression of fatigue crack growth in hydrogen-charged chrome molybdenum steel SCM 435 by cavitation peening employing a cavitating jet in water, a load controlled plate bending fatigue tests were conducted with load stress of 400 MPa after cathodic hydrogen charging with and without cavitation peening. The obtained results show crack growth rate were significantly accelerated by hydrogen charging. Number of cycle to failure from crack initiation of hydrogen-charged specimen increase 2.66 times by cavitation peening compared to an untreated one. It might be due to introducing compressive residual stress by cavitation peening.

  49. GS03 Effect of Mechanical Surface Treatment on Fatigue Strength of Duralumin Plate with a Hole

    SOYAMA Hitoshi, TAKEO Fumio

    2014　"GS03-1"-"GS03-3"　2014/07/19

    Publisher: The Japan Society of Mechanical Engineers

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    Mechanical surface treatments such as shot peening and cavitation peening are useful techniques to enhance fatigue strength of metallic materials. In order to establish mechanical surface treatments of mechanical components, the effects of geometry on enhancement of fatigue strength should be investigated. In the present paper, a plate with a hole as a typical shape, which had a corner and inner wall, was treated. The tested material was Duralumin Japanese Industrial Standards JIS A2017-T3. The plate was treated by shot peening and cavitation peening. Although the fatigue life of shot peened specimen was shorter than that of non-peened specimen, cavitation peening could improve fatigue life when the cavitation bubbles were shed and collapsed on the inner wall surface.

  50. Cavitation S Peening

    H. Soyama

    The Shot Peener　28　(3)　16-20　2014/07/01

    Publisher: Electronics Inc.

  51. Evaluation of Crack Initiation and Propagation of Stainless Steel Treated by Cavitating Peening Using a Load Controlled Plate Bending Fatigue Tester

    H. Soyama

    Metal Finishing News　15　(4)　60-62　2014/07/01

  52. 119 Effect of surface finishing on the hydrogen absorption at stainless steel

    TAKAKUWA Osamu, MANO Yuta, SOYAMA Hitoshi

    2014　(49)　39-40　2014

    Publisher: The Japan Society of Mechanical Engineers

  53. 136 Production of Hematite by Using Anodic Oxidation and its Thermoelectric Conversion Characteristic

    JUNICHO Naoya, SOYAMA Hitoshi

    2014　(49)　73-74　2014

    Publisher: The Japan Society of Mechanical Engineers

  54. 118 Effect of Tensile Prestrain on Mechanical Property of Ultrafine-Grained Metal

    UOJI Tomoki, AOYAGI Yoshiteru, SOYAMA Hitoshi

    2014　(49)　37-38　2014

    Publisher: The Japan Society of Mechanical Engineers

  55. 126 Effect of Cavitation Peening on Threshold Stress Intensity Factor Range of Chrome Molybdenum Steel

    KUMAGAI Naoki, TAKAKUWA Osamu, SOYAMA Hitoshi

    2014　(49)　53-54　2014

    Publisher: The Japan Society of Mechanical Engineers

  56. Effect of nozzle geometry on aggressivity of cavitating jet for cavitation erosion test and applications

    Satoshi Nishimura, Osamu Takakuwa, Hitoshi Soyama

    Fluid Mechanics and its Applications　106　283-302　2014

    Publisher: Kluwer Academic Publishers

    DOI： 10.1007/978-94-017-8539-6_12 　

    ISSN： 0926-5112

  57. 1405 Evaluation of Behavior of Dislocation Density and Crystal Orientation on Initiation and Propagation of Fatigue Crack

    IMAI Yuki, AOYAGI Yoshiteru, SOYAMA Hitoshi

    The Computational Mechanics Conference　2013　(26)　"1405-1"-"1405-2"　2013/11/02

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-026X

  58. 1402 Mechanical Property Evaluation of Grain Boundary by Indentation Test and Crystal Plasticity Simulation

    SAKUMA Sho, AOYAGI Yoshiteru, SOYAMA Hitoshi

    The Computational Mechanics Conference　2013　(26)　"1402-1"-"1402-2"　2013/11/02

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-026X

  59. OS2103

    TAKAKUWA Osamu, MANO Yuta, SOYAMA Hitoshi

    2013　"OS2103-1"-"OS2103-2"　2013/10/12

    Publisher: The Japan Society of Mechanical Engineers

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    In order to reveal the effect of indentation load on Vickers hardness of austenitic stainless steel after hydrogen charging, the Vickers hardness measurements have been conducted with three different indentation load of 0.49, 1.96 and 9.80 N. The obtained results show the Vickers hardness increases along with hydrogen charging time and the increase in the Vickers hardness depends on magnitude of indentation load. In the load of 0.49 N and 9.80 N, the Vickers hardness has a maximum value of 3.04 and 2.04 GPa which is 1.58 and 1.15 times larger than value of 1.73 and 1.70 GPa before hydrogen charging, respectively. It might be due to effect of hydrogen concentration gradient in respect to depth on deformation during indentation.

  60. 201 Effect of Shot Peening on Threshold Stress Intensity Factor Range in Stainless Steel

    NAITO Akima, TAKAKUWA Osamu, SOYAMA Hitoshi

    2013　(49)　31-32　2013/09/20

    Publisher: The Japan Society of Mechanical Engineers

  61. 202 Effect of Hydrogen Invasion on Macroscopic and Microscopic Strain at the surface of Stainless Steel

    MANO Yuta, TAKAKUWA Osamu, SOYAMA Hitoshi

    2013　(49)　33-34　2013/09/20

    Publisher: The Japan Society of Mechanical Engineers

  62. 312 Effect of Crystal Grain Size on Output Power of Cu_2O/Cu Solar Cell

    HASUDA Kenta, SOYAMA Hitoshi

    2013　(49)　93-94　2013/09/20

    Publisher: The Japan Society of Mechanical Engineers

  63. G031042 Estimating the Distribution of Compressive Residual Stress by Means of Impact Measurements

    NAITO Akima, TAKAKUWA Osamu, SOYAMA Hitoshi

    Mechanical Engineering Congress, Japan　2013　"G031042-1"-"G031042-5"　2013/09/08

    Publisher: The Japan Society of Mechanical Engineers

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    In this paper, the distribution of compressive residual stress caused by shot peening and cavitation peening was estimated by measurements of impact. It is known that the fatigue strength of metallic materials can be improved by introducing compressive residual stress induced by impact during peening process. The compressive residual stress at near surface and its distribution are important factors for improvement of the fatigue strength. In the case of shot peening, it is possible to estimate the distribution of compressive residual stress by numerical simulation using Hertz contact theory. However in the case of cavitation peening, it is hard to estimate residual stress distribution by numerical simulation. In this study, in order to estimate the distribution of compressive residual stress introduced by using shot peening and cavitation peening, plastic deformation pit and impact were measured. It is said that the compressive residual stress introduced region obtained by X-ray diffraction method can estimate by the maximum applied stress obtained by impact measurements and pit shape.

  64. G031041 Optimizing the Conditions for Residual Stress Measurement Using a Two-dimensional XRD Method

    TAKAKUWA Osamu, SOYAMA Hitoshi

    Mechanical Engineering Congress, Japan　2013　"G031041-1"-"G031041-5"　2013/09/08

    Publisher: The Japan Society of Mechanical Engineers

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    In order to optimize the conditions for residual stress measurement using a two-dimensional X-ray diffraction in terms of both efficiency and accuracy, the measurements were conducted on two specimens made of stainless steel in this study. The two specimens were treated by annealing and a cavitating jet in air so as to realize large grain and introduce residual stress. The specimens were oscillated in the ω- direction, representing a right-hand rotation of the specimen about the incident X-ray beam. The range of the oscillation, Δω, was varied and optimum Δω was determined. Moreover, combinations of the tilt angle between the specimen surface normal and the diffraction vector, ψ, with the rotation angle about its surface normal, φ, have been studied with a view to find the most optimum condition. The results show that the use of ω oscillations is an effective method for improving analysis accuracy, especially for large grain metals. The standard error rapidly decreased with increasing range of the co oscillation, especially for the annealed specimen which generated strong diffraction spots due to its large grain size.

  65. Cavitation Peening

    Hitoshi Soyama

    Bulletin of Japan Society of Spring Engineers　(503)　4311-4312　2013/08/01

    Publisher: Japan Society of Spring Engineers

  66. Enhancing the Resistance to Hydrogen Embrittlement in Stainless Steel by Cavitation Peening

    Osamu Takakuwa, Hitoshi Soyama

    Metal Finishing News　14　(4)　58-61　2013/07/01

  67. 渦電流法によるSUS316Lステンレス鋼の残留応力の評価

    祖山 均

    Inspection Engineering　18　(5)　6-10　2013/05/01

    Publisher: 日本工業出版

    ISSN： 1342-9825

  68. 147 Influence of Venturi Nozzle Outlet Geometry and Temperature on Cavitation Impact Energy

    TAGUCHI Takahiro, SOYAMA Hitoshi

    2013　(48)　96-97　2013/03/15

    Publisher: The Japan Society of Mechanical Engineers

  69. 149 Comparison of Evaluation Methods of Aggressive Intensity Induced by a Cavitating Jet

    SOYAMA Hitoshi, NAITO Akima

    2013　(48)　100-101　2013/03/15

    Publisher: The Japan Society of Mechanical Engineers

  70. 148 Effect of Nozzle Upstream Geometry on Cavitating Jet Aggressivity

    Nishimura Satoshi, SOYAMA Hitoshi

    2013　(48)　98-99　2013/03/15

    Publisher: The Japan Society of Mechanical Engineers

  71. 126 Effect of Hydrogen Invasion on Yield Stress at the Surface of Stainless Steel

    MANO Yuta, TAKAKUWA Osamu, SOYAMA Hitoshi

    2013　(48)　54-55　2013/03/15

    Publisher: The Japan Society of Mechanical Engineers

  72. 125 Effect of Cavitation Peening on Threshold Stress Intensity Factor Range in Stainless Steel

    SANADA Kazumasa, TAKAKUWA Osamu, SOYAMA Hitoshi

    2013　(48)　52-53　2013/03/15

    Publisher: The Japan Society of Mechanical Engineers

  73. 116 Effect of Sintering Condition During the Production of Fe_2O_3 by Sinter of FeOOH on Thermoelectric Conversion Characteristic

    JUNICHO Naoya, SOYAMA Hitoshi

    2013　(48)　36-37　2013/03/15

    Publisher: The Japan Society of Mechanical Engineers

  74. 132 Crystal Plasticity Simulation on Mechanical Property of Grain Boundary by Indentation

    AOYAGI Yoshiteru, SAKUMA Sho, TAKAKUWA Osamu, SOYAMA Hitoshi

    2013　(48)　66-67　2013/03/15

    Publisher: The Japan Society of Mechanical Engineers

  75. キャビテーションを活用した表面改質装置

    祖山 均

    油空圧技術　52　(3)　3-8　2013/03/01

    Publisher: 日本工業出版

    ISSN： 0914-6253

  76. 404 Surface Property Changes during Fatigue Process of Peened Case-Hardened Steel Rollers

    SEKI Masanori, ICHIHARA Taishi, NAGAHASHI Yuta, SOYAMA Hitoshi, KOBAYASHI Yuji, GOWA Daisuke, FUJII Masahiro

    2013　(51)　"404-1"-"404-2"　2013/02/25

    Publisher: The Japan Society of Mechanical Engineers

  77. Enhancing the Resistance to Fatigue Crack Growth in Steel Accelerated due to Hydrogen Charging by Cavitation Peening

    O. Takakuwa, H. Soyama

    Metal Finishing News　14　(4)　62-65　2013

  78. Technique for partially strengthening electrical steel sheet of IPM motor using cavitation peening

    O. Takakuwa, M. Nishikawa, H. Soyama

    Energy Materials: Materials Science and Engineering for Energy Systems　6　(1)　1422-1426　2012/12/01

    ISSN： 1748-9237

    eISSN： 1748-9245

  79. 214 Effect of Nozzle Outlet Geometry on Similarity Law of a Cavitating Jet

    NAITO Akima, SOYAMA Hitoshi

    2012　(48)　70-71　2012/09/22

    Publisher: The Japan Society of Mechanical Engineers

  80. 502 Effect of Ambient Gas on Spectrum of Mechano-Luminescence by Friction of Rocks

    MIYASAKA Kosuke, SOYAMA Hitoshi

    2012　(48)　148-149　2012/09/22

    Publisher: The Japan Society of Mechanical Engineers

  81. 411 Mechanical Property Evaluation of Grain Boundary by Indentation and Crystal Plasticity Simulation

    AOYAGI Yoshiteru, SAKUMA Sho, TAKAKUWA Osamu, SOYAMA Hitoshi

    2012　(48)　126-127　2012/09/22

    Publisher: The Japan Society of Mechanical Engineers

  82. 403 Evaluation of Surface Modificated Layer by Load-Controlled Plate Bending Fatigue Testing

    SANADA Kazumasa, TAKAKUWA Osamu, SOYAMA Hitoshi

    2012　(48)　110-111　2012/09/22

    Publisher: The Japan Society of Mechanical Engineers

  83. 404 Estimation of surface modification layer in stainless steel induced by cavitation peening

    TAKAKUWA Osamu, SOYAMA Hitoshi

    2012　(48)　112-113　2012/09/22

    Publisher: The Japan Society of Mechanical Engineers

  84. S112021 Effect of Cavitation Peening and Shot Peening on Fatigue Life of Case-Hardened Steel Rollers in a Case of Same Surface Roughness

    SEKI Masanori, SOYAMA Hitoshi, KOBAYASHI Yuji, GOWA Daisuke, FUJII Masahiro

    Mechanical Engineering Congress, Japan　2012　"S112021-1"-"S112021-3"　2012/09/09

    Publisher: The Japan Society of Mechanical Engineers

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    The purpose of this study is to investigate the effect of peening on the fatigue life of steel rollers. First, steel rollers were treated by three types of peenings to ensure the same surface roughness of peened rollers. One is the cavitation peening (CP) used a cavitating jet in water with an injection pressure of 30 MPa, and the others are the fine particle peening (FPP) with a shot diameter of 0.1 mm and the normal shot peening (NSP) with a shot diameter of 0.3 mm. The surface hardness and the surface compressive residual stress of the steel rollers were increased by all the peenings In particular, they were most increased by the FPP While, the work-hardened depth due to the CP and the NSP was larger than that due to the FPP. As a result of the roller tests, the fatigue lives of the steel rollers were improved by all the peenings, and they were most improved by the NSP. Judging from the P<max>-N curves and the [A(σ_y/Hv)]_<max>-N curves, the improvement m fatigue lives due to the FPP depended heavily on the increase in surface hardness due to that, and the effects of the CP and the NSP on the rolling contact fatigue were equivalent under the same surface roughness and the same surface hardness.

  85. Crystal Plasticity Simulation on Fatigue Crack Propagation in Steel and Effect of Residual Stress by Cavitation Peening

    Y. Aoyagi, O. Takakuwa, H. Soyama

    Metal Finishing News　13　(3)　58-60　2012/05

  86. 154 Effect of cavitation peening on the hydrogen-induced surface hardening at stainless steel surface

    TAKAKUWA Osamu, SOYAMA Hitoshi

    2012　(47)　114-115　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  87. 147 Effct of Cavitation Peening on Fatigue Crack Growth Rate in Stainless Steel

    SANADA Kazumasa, TAKAKUWA Osamu, SOYAMA Hitoshi

    2012　(47)　100-101　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  88. 129 Effect of the pressure of a field at cavitation bubble collapsing on cavitation peening

    NAITO Akima, TAKAKUWA Osamu, SOYAMA Hitoshi

    2012　(47)　64-65　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  89. 103 Effect of Oxidizing Condition of Cu_2O/Cu Solar Cell Produced by Anodic Oxidation

    HASUDA Kenta, SOYAMA Hitoshi

    2012　(47)　12-13　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  90. 180 Evaluation of Stress Anisotropy by Means of an Eddy Current Method with a Tangential-Rectangular Coil

    SEKINE Yuichi, SOYAMA Hitoshi

    2012　(47)　166-167　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  91. 179 Effect of Ambient Gas on Mechano-Luminescence of Rocks

    MIYASAKA Kosuke, SOYAMA Hitoshi

    2012　(47)　164-165　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  92. 138 Suppression of Fatigue Crack Growth in Stainless Steel by Laser Peening

    MORIYA Tomonori, TAKAKUWA Osamu, SANO Yuji, SOYAMA Hitoshi

    2012　(47)　82-83　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  93. 136 Parameters of Shedding Frequency of Cavitating Jet

    NISHIMURA Satoshi, TAKAKUWA Osamu, SOYAMA Hitoshi

    2012　(47)　78-79　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  94. 117 Effect of DownStream Geometry of Venturi Type Nozzle on Cavitation Aggressivity

    GONG Fangqi, SOYAMA Hitoshi

    2012　(47)　40-41　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  95. 131 Proposal of an Experimental Formula to Estimate Aggressivity of a Cavitating Jet

    SOYAMA Hitoshi

    2012　(47)　68-69　2012/03/13

    Publisher: The Japan Society of Mechanical Engineers

  96. サステイナブル社会のための表面改質

    祖山 均

    翠巒　(26)　12-15　2012/03

    Publisher: 青葉工学振興会

  97. 504 Relation between Work Hardening and Fatigue Life of Steel Gear Treated by Cavitation Peening

    SEKI Masanori, KAKUDA Masamitsu, SOYAMA Hitoshi, NAITO Akima, FUJII Masahiro

    2012　(50)　50401-50402　2012/02/28

    Publisher: The Japan Society of Mechanical Engineers

  98. G030053 Evaluation of Cavitation Peened Layer of SUS316L Stainless Steel Processed by Surface Machining Using Disk Grinder by Means of an Eddy Current Method

    SEKINE Yuichi, SOYAMA Hitoshi

    Mechanical Engineering Congress, Japan　2011　"G030053-1"-"G030053-3"　2011/09/11

    Publisher: The Japan Society of Mechanical Engineers

    More details Close

    For the use of structural components, most of the surface of austenitic stainless steel, JIS SUS316L, was ground to make a flat surface. When the grinding is conducted, tensile residual stress is induced at the surface. Introduction of the tensile residual stress is one of cause of stress corrosion cracking. To prevent the stress corrosion cracking, peening is conducted to introduce compressive residual stress. However, the surface roughness of the ground stainless steel treated after peening is seldom varied. Thus, the peening intensity treated after peening should be evaluated in case of the ground stainless steel. In the present report, to establish the non-destructive and relatively short-time evaluating method of the peening intensity, ground austenitic stainless steel using a disk grinder peened by cavitation peening is evaluated using an eddy current method with coil scanning. In results, the proper coil for the evaluation of ground stainless steel is existed, and the peened material can be evaluated by the eddy current method.

  99. GS16 Optimizing the Pitch of Cavitation Peening Using Toroidal Coodinate

    TAKAKUWA Osamu, SOYAMA Hitoshi

    2011　"GS16-1"-"GS16-3"　2011/07/16

    Publisher: The Japan Society of Mechanical Engineers

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    In this paper, the method for optimizing the pitch of cavitation peening based on Gaussian distribution is proposed. The Gaussian distribution showing the peening intensity was obtained by considering the white and black contrast of erosion ring caused in A1070 aluminum specimen by a cavitating jet in air. For evaluating the intensity of whole of the peened area, the intensity distribution was divided and summed using toroidal coordinate. The peening intensity distribution of erosion ring was summed with varying interval, and the optimum pitch of cavitation peening can be determined by the shape and height of intensity distribution.

  100. OS0318 Evaluation of the Distribution of Peening Efficiency of SUS316L Stainless Steel by Means of an Eddy Current Method

    SEKINE Yuichi, SOYAMA Hitoshi

    2011　"OS0318-1"-"OS0318-3"　2011/07/16

    Publisher: The Japan Society of Mechanical Engineers

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    To improve the fatigue strength and resistance to stress corrosion cracking, peening is the effective technique because of the introduction of compressive residual stress. As penetration depth can varies with frequency and electromagnetic properties are varied with the induced stress, an electromagnetic method is proper to evaluate the peening efficiency nondestructively. It was reported that the electromagnetic properties were varied with processing time of peening and depth where the compressive residual stress was introduced. In this paper, to establish the evaluating method of peening intensity and homogeneity after peening, austenitic stainless steel, JIS SUS316L treated by cavitation peening were evaluated by means of an eddy current method with coil scanning. In results, the peening intensity can be evaluated by the eddy current method.

  101. キャビテーションによる表面改質

    祖山 均

    Hydraulics & Pneumatics　50　(4)　6-11　2011/04/01

    Publisher: 日本工業出版

    ISSN： 0914-6253

  102. A Principle and Application of Cavitation Peening Technology

    祖山 均

    Bulletin of The Iron and Steel Institute of Japan　16　(4)　221-227　2011/04/01

    Publisher: The Iron and Steel Institute of Japan

    ISSN： 1341-688X

  103. 116 Effect of residual stress on corrosion behavior of stainless steel SUS316L

    Oyama Yosuke, Soyama Hitoshi

    2011　(46)　36-37　2011/03/15

    Publisher: The Japan Society of Mechanical Engineers

  104. 117 Evaluation of Thickness of the Surface Modified Layer of Alloy Tool Steel Treated by Cavitation Peening Using an Eddy Current Method

    SEKINE Yuichi, SOYAMA Hitoshi

    2011　(46)　38-39　2011/03/15

    Publisher: The Japan Society of Mechanical Engineers

  105. 122 Finite Element Analysis on the Dent Size and Plastic Deformation Area Generated by Surface Modification of Stainless Steel

    KANOU Shinya, NISHIKAWA Masaaki, SOYAMA Hitoshi

    2011　(46)　48-49　2011/03/15

    Publisher: The Japan Society of Mechanical Engineers

  106. 119 A Method Utilizing Bending Deformation to Identify the Yield Stress of Metal-Surface Modified Layer

    KAWARAGI Yusuke, NISHIKAWA Masaaki, SOYAMA Hitoshi

    2011　(46)　42-43　2011/03/15

    Publisher: The Japan Society of Mechanical Engineers

  107. 114 Observation of Mechano-Luminescence of Rocks

    SOYAMA Hitoshi

    2011　(46)　32-33　2011/03/15

    Publisher: The Japan Society of Mechanical Engineers

  108. 121 Evaluation of Yield Stress on Surface Modified Layer of Stainless Steel Subjected to Laser Peening

    MORIYA Tomonori, TAKAKUWA Osamu, SANO Yuji, NISHIKAWA Masaaki, SOYAMA Hitoshi

    2011　(46)　46-47　2011/03/15

    Publisher: The Japan Society of Mechanical Engineers

  109. 120 Suppression of Stress Corrosion Cracking for Stainless Steel by Re-Circulating Shot Peening Accelerated by a Water Jet

    NAITO Akima, TAKAKUWA Osamu, SOYAMA Hitoshi

    2011　(46)　44-45　2011/03/15

    Publisher: The Japan Society of Mechanical Engineers

  110. 812 Fatigue Life of Cavitation-Peened Steel Roller(Comparison with Shot-Peened Steel Roller)

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, KOZAI Seiya, NAITO Akima

    2011　(49)　227-228　2011/02/23

    Publisher: The Japan Society of Mechanical Engineers

  111. Fatigue Strength of Steel Rollers and Gears Treated by Cavitation Peening with Short Processing Time (A Case of Processing Time of 1 minute and 5 minutes)

    Masanori Seki, Naruto Nishie, Seiya Kozai, Masamitsu Kakuda, Hitoshi Soyama, Akima Naito, Masahiro Fujii

    Proceedings of The 4th International Conference on Manufacturing, Machine Design and Tribology (ICMDT2011)　7-8　2011

  112. 0417 Extermination of Zooplankton by Hydrodynamic Cavitation

    MURAOKA Taka, SOYAMA Hitoshi

    Fluids engineering conference ...　2010　153-154　2010/10/29

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-2882

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    With the aim of extermination of the zooplankton which is harmful for the environment and aquaculture in some cases by hydrodynamic cavitation using an enlarged pipe, treatment efficiency was enhanced by optimizing the diameter and length of the narrow area of the enlarged pipe. In addition, effect of the downstream pressure of narrow area of the enlarged pipe was measured. From the treatment of artemia and copepod, which were a kind of zooplankton, by hydrodynamic cavitation using optimized enlarged pipe, it was shown that the zooplankton was successfully exterminated using the hydrodynamic cavitation with an enlarged pipe, and the downstream pressure of narrow area of the enlarged pipe could be enhanced the treatment efficiency.

  113. 0413 Effect of Size and Injection Pressure of Nozzle on Ability of Cavitating Jet

    NAGASAKA Kazuya, TAKAKUWA Osamu, SOYAMA Hitoshi

    Fluids engineering conference ...　2010　145-146　2010/10/29

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-2882

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    Cavitation is well known as evil phenomenon which causes severe erosion in hydraulic machinery such as pumps, valves and propellers because of impacts produced at cavitation bubbles collapse. However, a cavitating jet which is a submerged high-speed water jet with cavitation is used for surface modification such as introduction of compressive residual stress and improvement of fatigue strength in the same way of shot peening. In order to enhance ability of cavitating jet which depend on nozzle throat diameter and injection pressure, an erosion test for aluminum and a measurement of compressive residual sterss of duralumin induced by cavitation peening were carried out.

  114. 0416 Measurement of Radical Produced by Hydrodynamic Cavitation Using Luminescent Analysis

    Soyama Hitoshi, Muraoka Taka

    Fluids engineering conference ...　2010　151-152　2010/10/29

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-2882

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    In order to use hot spot at cavitation bubble collapse for chemical reaction, luminescence at the collapse was carried out using a chemical luminescence analyzer. Hydrodynamic cavitation produced by injecting a high-speed water jet into a water filled chamber with cavitation bubble, i.e., a cavitating jet, was investigated. In the present paper, in order to find a suitable nozzle, intensity of luminescence produced by the cavitating jet at various nozzles was evaluated changing with injection pressure. The ultrasonic noise was also measured to evaluate aggressivity of the cavitating jet. The spectrum of the luminescence was evaluated to make clear mechanism of the luminescence. It was revealed that the spectrum of the luminescence induced by the cavitating jet was related to hydroxyl radical.

  115. 0412 Suppression of Hydrogen Embrittlement in Stainless Steel by Cavitation Peening

    TAKAKUWA Osamu, Nishikawa Masaaki, SOYAMA Hitoshi

    Fluids engineering conference ...　2010　143-144　2010/10/29

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-2882

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    In the use of hydrogen energy, the hydrogen embrittlement should be investigated, and it is necessary to improve reliability and safety of machine components which are used in hydrogen environment. The hydrogen sensitivity of material depends on material structure, defect, and stress distribution. There is a possibility that the hydrogen invasion into material and the fatigue crack propagation with hydrogen embrittlement can be suppressed by introducing compressive residual stress using surface modification such as cavitation peening. In this study, the specimens made of austenite stainless steel JIS SUS316L with precrack were charged by a cathodic hydrogen charging method, and the fatigue test was conducted by a plate bending fatigue test.

  116. 014 Effect of Velocity and Scale of Cavitating Jet on Cavitation Peening

    SOYAMA Hitoshi

    2010　369-371　2010/10/09

    Publisher: The Japan Society of Mechanical Engineers

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    Although cavitation impacts normally cause severe damage in hydraulic machinery such as pumps and valves, they can be used for peening in the same way of shot peening. The peening method using cavitation impacts is named as cavitation peening. At the cavitation peening, cavitation was generated by injecting a high-speed waterjet into a water filled chamber. This sort ofjet is called as a cavitating jet. In the case of the cavitating jet, aggressivity of the cavitation impact is increasing with scale and / or injection pressure, i.e., velocity at the nozzle of the jet In order to establish cavitation peening, the effect of the scale and the velocity of the cavitating jet on the cavitation peening was investigated. The residual stress of stainless steel JIS316L introduced by the cavitating jet was evaluated at various injection pressure and nozzle size. It was revealed that the introduced compressive residual stress was increased with the nozzle size from 0.35 mm to 2 mm. The compressive residual was nearly constant when the injection pressure increased from 100 MPa to 300 MPa. At constant jet power, compressive residual stress introduced by the large size cavitating jet at low injection pressure was larger than that of small cavitating jet at high injection pressure.

  117. 013 Numerical Analysis on the Retardation Effect of Fatigue Crack Growth of Stainless Steel by Cavitation Peening

    NISHIKAWA Masaaki, TAKAKUWA Osamu, YAMAMIYA Kohei, SOYAMA Hitoshi

    2010　366-368　2010/10/09

    Publisher: The Japan Society of Mechanical Engineers

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    Cavitation peening (CP) is one of the surface modification techniques for metallic materials to introduce an equibiaxial compressive residual stress on their surface and it was demonstrated that the CP significantly decreases the fatigue crack growth rate on the modified surface during a plate bending fatigue test. To understand the mechanism underlying the peening effect, the present study presented a numerical model to address the crack retardation using a fatigue cohesive zone model. The present cohesive zone model incorporates the static fracture based on fracture mechanics and the fatigue damage accumulation based on damage mechanics. Using the finite element model, we investigated the effect of the surface residual stress introduced by CP for austenite stainless steel SUS316L, which was reported by our previous literature, on the retardation of crack growth. The simulated results demonstrated that the equibiaxial compressive residual stress is a main factor causing the crack retardation

  118. Introduction of compressive residual stress by cavitation peening

    Osamu Taakakuwa, Masaaki Nishikawa, Hitoshi Soyama

    Journal of the Japan Society for Abrasive Technology　54　(10)　574-577　2010/10/01

    Publisher: 砥粒加工学会

    ISSN： 0914-2703

  119. G0300-7-1 Evaluation of equibiaxial residual stress to metal surface using micro-indentation tests

    NISHIKAWA Masaaki, SOYAMA Hitoshi

    The proceedings of the JSME annual meeting　2010　(1)　231-232　2010/09/04

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemecjo.2010.1.0_231 　

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    The present study proposed a method to evaluate equibiaxial compressive residual stress of metal surface by means of depth-sensing indentation method with a spherical indenter. In particular, an inverse analysis using elastic-plastic finite element model for an indentation test was established to evaluate the residual stress from the indentation load-displacement curve. The proposed inverse analysis utilizes two indentation test results for a reference specimen whose residual stress is already known and for a target specimen whose residual stress is unknown, in order to exclude the effect of other unknown mechanical properties, such as Young's modulus and yield stress. The residual stress identified by using the indentation method is almost identical to that measured by X-ray diffraction, and the difference of the residual stress between these two methods ranges within 36 %, when the indentation loads are from 0.49 N to 0.98 N. Therefore, it can be concluded that the proposed method can effectively evaluate the residual stress on the metal surface.

  120. Suppression of Fatigue Crack Propagation in Steel by Cavitation Peening

    O. Takakuwa, M. Nishikawa, H. Soyama

    Metal Finishing News　11　(4)　58-60　2010/07

  121. 136 Effect of Strain Rate on the Yield Stress of Stainless Steel after Peening

    KANOU Shinnya, NISHIKAWA Masaaki, SOYAMA Hitoshi

    2010　(45)　74-75　2010/03/12

    Publisher: The Japan Society of Mechanical Engineers

  122. 137 A Quantitative Method to Identify the Yield Stress of Metals by Micro-Indentation Tests with a Spherical Indenter

    KAWARAGI Yusuke, NISHIKAWA Masaaki, SOYAMA Hitoshi

    2010　(45)　76-77　2010/03/12

    Publisher: The Japan Society of Mechanical Engineers

  123. 20407 Evaluation of modified surface of metals by indentation tests using a spherical indenter

    NISHIKAWA Masaaki, TAKAKUWA Osamu, SOYAMA Hitoshi

    2010　(16)　137-138　2010/03/09

    Publisher: The Japan Society of Mechanical Engineers

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    The present study presents an inverse analysis technique to determine the yield stress on the modified surface of metals. The method utilizes a depth-sensing instrumented indentation technique using a spherical indenter. Especially, a strategy of inverse analysis using finite element analyses has been established to determine the yield stress from the results of indentation tests. First, using a damage mechanics model, we revealed that the indentation load-depth curve is influenced by the degradation of Young's modulus, due to the damage effect at a highly-deformed plastic region under the tip of the indenter. Therefore, we present the method to evaluate the yield stress on the modified surface, excluding the damage effect. We applied the method to evaluate the yield stress of SUS 316L modified by cavitation peening.

  124. 512 Relationship between Improvement in Fatigue Life of Steel Gear and Increase in Hardness due to Cavitation Peening

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, NISHIE Naruto, KAKUDA Masamitsu, YOSHIDA Akira

    2010　(48)　151-152　2010/02/24

    Publisher: The Japan Society of Mechanical Engineers

  125. 520 Improvement in Sliding Property of Steel by Cavitation Peening

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, YOSHIDA Akira

    59　377-378　2010

    Publisher: 日本材料学会

  126. 519 Inspection of Peening Methods on Improvement of Fatigue Strength of Welded Parts

    SOYAMA Hitoshi, TAKAKUWA Osamu, OYAMA Yosuke

    59　375-376　2010

    Publisher: 日本材料学会

  127. 319 Fatigue Growth Behavior of Surface Crack in Stainless Steel Modified by Cavitation Peening

    NISHIKAWA Masaaki, TAKAKUWA Osamu, SOYAMA Hitoshi

    59　101-102　2010

    Publisher: 日本材料学会

  128. 気泡崩壊による衝撃力を利用した歯車の疲労強度向上

    關 正憲, 祖山 均

    ANNUAL REPORT OF THE OKAYAMA FOUNDATION FOR SCIENCE AND TECHNOLOGY　2010　100-107　2010

  129. ピーニングされた表面の摩擦・摩耗特性(S45C焼入れ材の場合)

    二田 誠一郎, 藤井 正浩, 關 正憲, 祖山 均, 小林 祐次, 吉田 彰

    社団法人日本設計工学会研究発表講演会講演論文集　2009　(2)　51-54　2009/10/23

  130. 205 Hydroxyl Radical Generated by Hydrodynamic Cavitation

    SOYAMA Hitoshi, MURAOKA Taka

    2009　(45)　49-50　2009/09/26

    Publisher: The Japan Society of Mechanical Engineers

  131. 204 Pro-oxidant Activity of Pressure Vessel Steel by Cavitation Residual Bubbles

    SOYAMA Hitoshi

    2009　(45)　47-48　2009/09/26

    Publisher: The Japan Society of Mechanical Engineers

  132. Indentation Technique for Characterization of the Metal Surface Modified by Cavitation Peening

    M. Nishikawa, H. Soyama

    Metal Finishing News　10　(6)　58-60　2009/09

  133. OS1203 Evaluation of Micro-Strain in Stainless Steel by Fundamental Approach

    SOYAMA Hitoshi, OYAMA Yosuke

    2009　648-650　2009/07/24

    Publisher: The Japan Society of Mechanical Engineers

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    In order to make clear mechanism of fatigue fracture and improvement of fatigue strength by cavitation peening, micro-strain was evaluated by using a fundamental approach. In the previous reports, micro strain induced by heat treatment and/or mechanical finishing was decreased by cavitation peening. As the micro strain might be a source of fatigue crack, the decrease of the micro strain causes improvement of fatigue strength. In the present paper, the micro strain of stainless steel was measured by the fundamental approach, which was one X-ray diffraction method and normally used for the measurement of grain size and micro strain of nano-size powder. The micro strain before and after cavitation peening and the micro strain changing with fatigue cycles were investigated. It was revealed that the micro strain induced by grinding was decreased by cavitation peening. The micro strain was changing with fatigue cycles.

  134. 128 Effect of Cuprous Oxide Density in Copper on Performance of Cuprous Oxide Solar Cell

    ISHIBASHI Takao, NAGASAKO Makoto, KAINUMA Ryosuke, SOYAMA Hitoshi

    2009　(44)　54-55　2009/03/13

    Publisher: The Japan Society of Mechanical Engineers

  135. 129 Effect of Residual Stress Induced by Surface Treatment on Fatigue Strength of Stainless steel

    TAKAKUWA Osamu, SOYAMA Hitoshi

    2009　(44)　56-57　2009/03/13

    Publisher: The Japan Society of Mechanical Engineers

  136. 101 Evaluation of Equibiaxial Stress by Means of an Eddy Current Method

    SEKINE Yuichi, SOYAMA Hitoshi

    2009　(44)　2-3　2009/03/13

    Publisher: The Japan Society of Mechanical Engineers

  137. 127 Evaluation of Shear Stress by Using X-ray Diffraction Methods

    SOYAMA Hitoshi

    2009　(44)　52-53　2009/03/13

    Publisher: The Japan Society of Mechanical Engineers

  138. 908 Surface Properties and Pitting Strength of Cavitation-Peened Steel Roller

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, FUJII Isao, KAYAMA Hayato, NISHIZAWA Kazuto, SEKINE Yuichi, YOSHIDA Akira

    2009　(47)　303-304　2009/02/26

    Publisher: The Japan Society of Mechanical Engineers

  139. S1105-1-1 Improvement of friction characteristics on the surface of spheroidal graphite cast iron by cavitation peening

    Hitoshi SOYAMA, Takahiro SHINNOKI, Takeshi YAMAGUCHI, Kazuo HOKKIRIGAWA

    The proceedings of the JSME annual meeting　2009.4　165-166　2009

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmemecjo.2009.4.0_165 　

    eISSN： 2433-1325

  140. Improvement in Fatigue Strength of Steel Gear by Next-Generation Cavitation Peening

    SEKI M., SOYAMA Hitoshi, YOSHIDA Akira

    Proc. JSME MPT2009　317　317-322　2009

    Publisher: The Japan Society of Mechanical Engineers

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    A new cavitation peening processing unit was made to obtain greater peening effect. The purpose of this study is to investigate the improvement in fatigue strength of the steel gear cavitation-peened using this processing unit. The case-hardened steel rollers and gears were cavitation -peened under a processing time of 1 minute, and were fatigue-tested using a roller testing machine and a gear testing machine. The hardness and the compressive residual stress of the test specimens were increased by the cavitation peening. While, the surface roughness of the cavitation-peened test specimens was almost the same to that of the non-peened ones. In the fatigue tests, the fatigue life of the cavitation-peened test specimens was longer than that of the non-peened ones. Moreover, the fatigue strength of the test specimens was increased by the cavitation peening. This study revealed that the fatigue strength of steel gear was improved by the cavitation peening under a processing time of 1 minute.

  141. 413 Improvement of Yield Stress in Surface-Modification-Layer of Stainless Steel by Cavitation Peening

    SOYAMA Hitoshi, MAEDA Toshiyuki

    58　289-290　2009

    Publisher: 日本材料学会

  142. Effect of Cavitation Peening on Tribological Characteristics of Carbon Steel

    Masanori Seki, Masahiro Fujii, Hitoshi Soyama, Akira Yoshida

    Proceedings of World Tribology Congress 2009　694　2009

  143. B05 Increase in Fatigue Strength of Steel Gear by Next-Generation Cavitation Peening

    SEKI Masanori, SOYAMA Hitoshi, YOSHIDA Akira

    2008　55-56　2008/10/06

    Publisher: The Japan Society of Mechanical Engineers

  144. B03 Increase in Fatigue Life of Case-Hardened Steel Gear by Cavitating Jets in Water and Air

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, TOBITA Yoshiki, NISHIE Naruto, NISHIZAWA Kazuto, YOSHIDA Akira

    2008　51-52　2008/10/06

    Publisher: The Japan Society of Mechanical Engineers

  145. 117 High-Speed Observation of a Cavitating Jet with Associated Water Jet

    NISHIZAWA Kazuto, MIKAMI Mitsuhiro, SOYAMA Hitoshi

    2008　(44)　33-34　2008/09/27

    Publisher: The Japan Society of Mechanical Engineers

  146. 114 Optimization of Coil for Evaluation of Surface Modification Layer by Eddy Current Method

    SEKINE Yuichi, SOYAMA Hitoshi

    2008　(44)　27-28　2008/09/27

    Publisher: The Japan Society of Mechanical Engineers

  147. GS0101 Relationship between peening effects and work hardening on peening treated Type 316L

    MASAKI Kiyotaka, OCHI Yasuo, SOYAMA Hitoshi, SANO Yuji

    2008　"GS0101-1"-"GS0101-2"　2008/09/16

    Publisher: The Japan Society of Mechanical Engineers

  148. 軽く安くする材料・加工技術 第11回 ショットを使わないピーニング

    祖山 均

    日経Automotive Technology　(7)　156-161　2008/07/01

    Publisher: 日経BP社

    ISSN： 1881-9362

  149. 1213 Surface Durability of Cavitation-Peened Steel Gear

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, TOBITA Yoshiki, NISHIE Naruto, YOSHIDA Akira

    The Machine Design and Tribology Division meeting in JSME　2008　(8)　89-92　2008/04/20

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-3919

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    In order to investigate the effect of cavitation peening on surface durability of steel gears, the case-hardened steel rollers and gears cavitation-peened under different conditions were fatigue-tested using a roller testing machine and a gear testing machine. The hardness and the compressive residual stress of the test rollers and gears were increased by the cavitation peening. On the other hand, their surface roughness was not increased so much. In the roller tests, the fatigue life of all the cavitation-peened rollers was longer than that of the non-peened roller. In the gear tests, the surface durability of the test pinions was improved by the cavitation peening. Judging from the relationships between the maximum stress amplitude and the surface roughness, it was clear that the surface durability of steel gears was improved by the increase in surface hardness due to the cavitation peening with little influence of surface roughness.

  150. 群列キャビテーションによる金属材料の表面改質

    祖山 均

    熱処理　48　(2)　74-78　2008/04

  151. 194 Evaluation of Sub-Surface of Tool Steel Treated by Cavitation Shotless Peening using Indentation Method

    MAEDA Toshiyuki, SOYAMA Hitoshi

    2008　(43)　189-190　2008/03/15

    Publisher: The Japan Society of Mechanical Engineers

  152. 224 Introduction of Oxidation-Induced Stacking Faults in Silicon Wafer through SiO_2 Layer by Cavitation Jet

    KAI Akira, SOYAMA Hitoshi

    2008　(43)　249-250　2008/03/15

    Publisher: The Japan Society of Mechanical Engineers

  153. 195 Corrosion Behavior of Rolled Steels for General Structure Exposed to Residual Cavitation Bubbles

    GOTO Yoshihiro, KAI Akira, SOYAMA Hitoshi

    2008　(43)　191-192　2008/03/15

    Publisher: The Japan Society of Mechanical Engineers

  154. 134 Residual Stress in Sub-Surface of Alloy Toll Steel Induced by Surface Finishing and Its Control

    TAKAKUWA Osamu, SOYAMA Hitoshi

    2008　(43)　69-70　2008/03/15

    Publisher: The Japan Society of Mechanical Engineers

  155. 132 Evaluation of Surface Modification Layer of Alloy Tool Steel by Means of Eddy Current Method

    SEKINE Yuichi, SOYAMA Hitoshi

    2008　(43)　65-66　2008/03/15

    Publisher: The Japan Society of Mechanical Engineers

  156. 919 Effect of Cavitation Peening on Fatigue Life of Steel Roller

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, MISHIMA Takahiro, FUJII Isao, YOSHIDA Akira

    2008　(46)　359-360　2008/02/26

    Publisher: The Japan Society of Mechanical Engineers

  157. 915 Effect of Cavitation Peening on Fatigue Life of Steel Gear

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, TONOGOCHI Tetsuya, TOBITA Yoshiki, YOSHIDA Akira

    2008　(46)　351-352　2008/02/26

    Publisher: The Japan Society of Mechanical Engineers

  158. 616 Application of Cavitation Peening to Improvement in Fatigue Life of Steel Gear

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, YOSHIDA Akira

    57　165-166　2008

    Publisher: 日本材料学会

  159. Effect of Cavitation Shotless Peening on Fatigue Strength of Steel Gear

    Masanori Seki, Hitoshi Soyama, Masahiro Fujii, Akira Yoshida

    Conference Proceedings of the 10th International Conference on Shot Peening　99-104　2008

  160. 101 Increase in Fatigue Strength of Steel Gear by Cavitation Shotless Peening

    SEKI Masanori, SOYAMA Hitoshi, FUJII Masahiro, YOSHIDA Akira

    The JSME Symposium on Motion and Power Transmissions　2007　23-26　2007/11/29

    Publisher: The Japan Society of Mechanical Engineers

    More details Close

    In order to investigate the effect of cavitation shotless peening on fatigue strength of steel gears, the case-hardened steel rollers and gears cavitation shotless peened under different conditions were fatigue-tested using a roller testing machine and a gear testing machine. The hardness and the compressive residual stress of the test rollers and gears were increased by cavitation shotless peening. On the other hand, their surface roughness was not increased so much. In the fatigue tests, the fatigue life of most cavitation shotless peened rollers and gears was longer than that of the non-peened roller and gear. In particular, the fatigue life of cavitation shotless peened rollers and gears was significantly improved by using a modified nozzle for a high-speed water jet to obtain a greater peening effect. Therefore, it was found that the cavitation shotless peening is good for the increase in fatigue strength of steel gears.

  161. 801 New Era of Research and Development on Cavitation Peening

    SOYAMA Hitoshi

    2007　568-569　2007/10/24

    Publisher: The Japan Society of Mechanical Engineers

    More details Close

    Cavitation normally courses severe damage in hydraulic machinery such as pumps and valves, as severe impacts were produced at cavitation bubble collapses. However, cavitation impact was utilized for surface improvement in the same way as shot peening. Peening method using cavitation impacts was called "cavitation peening CP" or "cavitation shotless peening CSP", as shots were not required. The great advantage of cavitation peening was that surface roughness after peening was very smooth compared with that of shot peening, because of no solid collision. Recently, new system for cavitation has been developed to enhance cavitation impact to increase peening effects such as fatigue strength, introduction of compressive residual stress and work hardening. This research and development was partly supported by Ministry of Economy, Trade and Industry.

  162. 609 Fatigue Strength Improvement of Element for CVT Steel Belt by Cavitation Shotless Peening

    SOYAMA Hitoshi, Shimizu Masanori, Hattori Yuji, Nagasawa Yuji

    2007　444-444　2007/10/24

    Publisher: The Japan Society of Mechanical Engineers

  163. 103 Corrosion Behavior of Pressure Vessel Steel Exposed to Residual Cavitation Bubbles

    GOTO Yoshihiro, KAI Akira, SOYAMA Hitoshi

    2007　(43)　5-6　2007/09/29

    Publisher: The Japan Society of Mechanical Engineers

  164. 101 Evaluation of Young's Modulus of Sub-Surface Treated by Cavitation Shotless Peening by Bending Beam

    MAEDA Toshiyuki, SOYAMA Hitoshi

    2007　(43)　1-2　2007/09/29

    Publisher: The Japan Society of Mechanical Engineers

  165. 102 Effect on Residual Stress in Sub-Surface by Surface Finish

    TAKAKUWA Osamu, SOYAMA Hitoshi, YAMADA Nao

    2007　(43)　3-4　2007/09/29

    Publisher: The Japan Society of Mechanical Engineers

  166. Shield Cavitation Shotless Peening and Its Application for Welded Parts

    Akira Kai, Hitoshi Soyama

    Metal Finishing News　8　(5)　48-50　2007/09

  167. 群列キャビテーションとその金属材料の表面改質への有効利用

    祖山 均, 甲斐 彰

    フルードパワーシステム　38　(5)　243-247　2007/09

  168. (6)Cavitation Shotless Peening for Surface Modification of Alloy Tool Steel

    Odhiambo Dan

    Journal of the Japan Society of Mechanical Engineers　110　(1062)　341-341　2007/05/05

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 0021-4728

  169. 141 Releasing of Strain in Grain of Alloy Tool Steel by Cavitation Shotless Peening

    SOYAMA Hitoshi, YAMADA Nao

    2007　(42)　81-82　2007/03/13

    Publisher: The Japan Society of Mechanical Engineers

  170. 916 Improvement in Fatigue Life of Case-Hardened Steel Gear by Cavitation Shotless Peening

    SEKI Masanori, SOYAMA Hitoshi, TONOGOCHI Tetsuya, TOBITA Yoshiki, YOSHIDA Akira

    2007　(45)　357-358　2007/03/07

    Publisher: The Japan Society of Mechanical Engineers

  171. 910 A Fundamental Study on Fatigue Life of Cavitation Shotless Peened Steel Roller

    SEKI Masanori, SOYAMA Hitoshi, MISHIMA Takahiro, FUJII Isao, YOSHIDA Akira

    2007　(45)　345-346　2007/03/07

    Publisher: The Japan Society of Mechanical Engineers

  172. 317 Improving accuracy for Residual Stress Measurement using Two Dimensional Detector by Omega Scan

    YAMADA Nao, TAKAKUWA Osamu, SOYAMA Hitoshi

    56　251-252　2007

    Publisher: 日本材料学会

  173. Fabrication of a GaAs microwave probe used for atomic force microscope Peer-reviewed

    Yang Ju, Tetsuya Kobayashi, Hitoshi Soyama

    IPACK 2007: PROCEEDINGS OF THE ASME INTERPACK CONFERENCE 2007, VOL 1　963-966　2007

  174. Molecular beam epitaxial growth and characterization of defects induced by cavitation impacts on polysilicon thin films

    D. O. Macodiyo, H. Soyama, K. Hayashi

    PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY　61　750-754　2007

    DOI： 10.1088/1742-6596/61/1/150 　

    ISSN： 1742-6588

  175. Macro and Micro Strain in Polycrystalline Metal Controlled by Cavitation Shotless Peening

    Hitoshi Soyama

    Metal Finishing News　7　(6)　48-50　2006/11

  176. キャビテーション・ピーニングによる金属材料の表面改質

    祖山 均

    まてりあ　45　(9)　657-663　2006/09

    Publisher: The Japan Institute of Metals and Materials

    DOI： 10.2320/materia.45.657 　

    ISSN： 1340-2625

  177. 2209 Fatigue Life of Cavitation Shotless Peened and Shot Peened Steel Gears

    SEKI Masanori, SOYAMA Hitoshi, OHUE Yuji, YOSHIDA Akira

    The Machine Design and Tribology Division meeting in JSME　2006　(6)　213-216　2006/05/28

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-3919

    More details Close

    In order to investigate the influence of peening on the fatigue life of steel gears, the steel rollers and gears cavitation shotless peened and shot peened with different conditions were fatigue-tested using a roller testing machine and a gear testing machine. The hardness and the compressive residual stress of test rollers and gears increased by these peenings. The surface roughness of those increased by the shot peening, whereas those did not increase so much by the cavitation shotless peening. In the fatigue tests, the fatigue life of most shot peened gears was as long as that of the non peend gear in this experimental range. On the other hand, the fatigue life of most cavitation shotless peened rollers and gears was longer than that of the non peend roller and gear. It follows from these that the cavitation shotless peening is good for the increase in fatigue life of steel gears, because the surface roughness does not increase so much by cavitation shotless peening.

  178. 520 Microfabrication of gallium arsenide cantilever for Atomic Force Microscopy

    KOBAYASHI Tetsuya, JU Yang, SOYAMA Hitoshi

    2006　(41)　231-232　2006/03/14

    Publisher: The Japan Society of Mechanical Engineers

  179. 515 Improvement of Cavitation Erosion Resistance of Stainless Steel by Cavitation Peening

    SOYAMA Hitoshi, YAMAZAKI Yuki

    2006　(41)　221-222　2006/03/14

    Publisher: The Japan Society of Mechanical Engineers

  180. Improvement of Fatigue Strength of Metallic Materials by Cavitation Shotless Peening

    Hitoshi Soyama

    Metal Finishing News　7　(2)　48-50　2006/03

  181. 912 Fatigue Life of Cavitation Shotless Peened Steel Gears

    SEKI Masanori, SOYAMA Hitoshi, YOSHIDA Akira, TONOGOCHI Tetsuya

    2006　(44)　361-362　2006/02/23

    Publisher: The Japan Society of Mechanical Engineers

  182. Surface Modification of Light Metallic Materials by Using Cavitation Shotless Peening

    祖山 均

    軽金属　56　(1)　56-62　2006/01/30

    Publisher: 軽金属学会

    DOI： 10.2464/jilm.56.56 　

    ISSN： 0451-5994

  183. 235 Measurement of Residual Stress of Cuprous Oxide by Means of Two Dimensional Position Sensitive Proportional Counter

    SOAYAM Hitoshi, TSUCHINAGA Makoto, YAMADA Nao

    55　261-262　2006

    Publisher: 日本材料学会

  184. Characterization of Defects for Effective Gettering in Silicon Wafer and Polysilicon

    Dan O. Macodiyo, H. Soyama, K. Hayashi

    Thin Films　(ESDA2006-95340)　1-10　2006

  185. 2005 American Waterjet Conference

    SOYAMA Hitoshi

    Journal of the Japan Society for Abrasive Technology　49　(12)　673-676　2005/12/01

    Publisher: 砥粒加工学会

    ISSN： 0914-2703

  186. G803 Unsteady Behavior of a Cavitating Jet in Air

    SOYAMA Hitoshi

    Fluids engineering conference ...　2005　320-320　2005/10/28

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-2882

  187. 210 C-V Characteristic of Backside Damage Gettering Introduced by a Cavitating Jet

    SOYAMA Hitoshi, SAITO Suguru, MACODIYO Dan O., KOYANAGI Mitsumasa

    2005　(40)　70-71　2005/03/15

    Publisher: The Japan Society of Mechanical Engineers

  188. 809 A Fundamental Study on Improvement in Surface Durability of Cavitation Shotless Peened Steel Rollers

    SEKI Masanori, SOYAMA Hitoshi, YOSHIDA Akira, Mishima Takahiro

    2005　(43)　293-294　2005/02/24

    Publisher: The Japan Society of Mechanical Engineers

  189. 518 Distribution of Residual Stress around Plastic Deformation Pit Induced by Cavitation Shotless Peening

    Hitoshi SOYAMA

    Proceedings of the 1992 Annual Meeting of JSME/MMD　2005　361-362　2005

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmezairiki.2005.0_361 　

    eISSN： 2433-1287

  190. 118 Fatigue Property Improvement of SUS316L Steel by Cavitation Shotless Peening

    YASUDA Keisuke, MASAKI Kiyotaka, OCHI Yasuo, MATSUMURA Takashi, SOYAMA Hitoshi

    54　223-224　2005

    Publisher: 日本材料学会

  191. 139 Application of Cavitation Shotless Peening to Narrow Pipe

    SOYAMA Hitoshi, SHINOZAKI Yuichi

    54　265-266　2005

    Publisher: 日本材料学会

  192. 722 Electrical Characteristics of Cuprous Oxide Solar Cell under Bending Stress

    SOYAMA Hitoshi, TSUCHINAGA Makoto

    54　459-460　2005

    Publisher: 日本材料学会

  193. マイクロ波による半導体材料の導電率の定量評価手法の開発 Peer-reviewed

    巨 陽, 大野 悌, 祖山 均, 坂 真澄

    日本AEM学会誌　13　(1)　32-37　2005

  194. Estimation of Residual Stress of Metallic Materials by Indentation Method

    Symposium on Evaluation and Diagnosis　2004　(3)　90-93　2004/12/15

    Publisher: The Japan Society of Mechanical Engineers

  195. Three Dimensional Forming of Duralumin Plate by Using Cavitating Jet in Air

    SOYAMA Hitoshi, MIKAMI Mitsuhiro

    2004　(40)　201-202　2004/09/17

    Publisher: The Japan Society of Mechanical Engineers

  196. 202 Characteristics of Photovoltaics of Cuprous Oxide under Bending Stress

    SOYAMA Hitoshi, TSUCHINAGA Makoto

    2004　(39)　48-49　2004/03/13

    Publisher: The Japan Society of Mechanical Engineers

  197. 405 キャビテーション・ショットレス・ピーニングによる歯車の疲労強度向上(破壊の進展とその抑制,破壊の発生・進展とその評価および抑制,オーガナイスドセッション・8,第53期学術講演会)

    祖山 均, Macodiyo Dan Odhiambo

    学術講演会講演論文集　53　99-100　2004

    Publisher: 日本材料学会

  198. 206 Monitoring of Pitting Damage by Laser Doppler Vibrometer

    SOYAMA Hitoshi, HOMMA Kana

    The Proceedings of Conference of Tohoku Branch　2004　(0)　56-57　2004

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmeth.2004.39.56 　

  199. Cavitation Shotless Peening

    Hitoshi Soyama

    Journal of Japan Society of Mechanical Engineers　107　(1022)　53-53　2004/01

    Publisher: 一般社団法人日本機械学会

    ISSN： 0021-4728

  200. Fracture, its evaluation and suppression III: Surface modification for suppression of crack initiation and propagation

    Hitoshi Soyama

    Zairyo/Journal of the Society of Materials Science, Japan　53　(7)　826-832　2004

    Publisher: Society of Materials Science Japan

    DOI： 10.2472/jsms.53.826 　

    ISSN： 0514-5163

  201. Microwave Evaluation of the Shape and Size of 3-D Cracks on the Metal Surface

    JU Yang, UCHIMURA Yasuhiro, SOYAMA Hitoshi, SAKA Masumi

    Symposium on Evaluation and Diagnosis　2003　(2)　147-149　2003/12/02

    Publisher: The Japan Society of Mechanical Engineers

    More details Close

    Crack is the most dangerous defect in machines and structures. Cracking often initiates from the surface of materials, since the surface stress is often higher than the stress of inside when a metal is under load. Nondestructive evaluation of a small crack is always regarded as a difficult but an utmost important issue for the integrity assessment of structural components. Recently, small cracks have been detected successfully by using microwaves under a condition of no contact and without any coupling medium, and a dual frequency technique has been developed to evaluate the size of surface cracks in metals. In the present paper, a study of evaluation of the shape and size of 3-D cracks using an enhanced microwave dual frequency technique is reported.

  202. The Effect of Curvature of the Substrate on Photovoltaics of Cuprous Oxide

    SOYAMA Hitoshi, TANASE Ryota

    2003　(39)　53-54　2003/09/05

    Publisher: The Japan Society of Mechanical Engineers

  203. Numerical Simulation of Coverage of Cavitation Impacts Changing with Time

    SOYAMA Hitoshi, Futakawa Masatoshi

    2003　(39)　73-74　2003/09/05

    Publisher: The Japan Society of Mechanical Engineers

  204. Development of Cavitation Shotless Peening System

    Hitoshi Soyama

    Hydraulics & Pneumatics　42　(8)　35-39　2003/08

  205. Effect of Stress on Photovoltaics of Cuprous Oxide

    SOYAMA Hitoshi, TANASE Ryota, SAKA Masumi

    2003　(38)　198-199　2003/03/15

    Publisher: The Japan Society of Mechanical Engineers

  206. Development of Cavitation Sensor for Strong Impacts

    SOYAMA Hitoshi, SAITO Kenich

    2003　(38)　42-43　2003/03/15

    Publisher: The Japan Society of Mechanical Engineers

  207. Improvement of Fatigue Strength of Mechanical Material by a Cavitating Jet in Air

    SAITO Kenichi, SOYAMA Hitoshi, SAKA Masumi

    2003　(38)　58-59　2003/03/15

    Publisher: The Japan Society of Mechanical Engineers

  208. Predicition of Cavitation Erosion

    Hitoshi Soyama

    The Piping Engineering　45　(2)　9-14　2003/02

    Publisher: 日本工業出版

    ISSN： 0385-9894

  209. ステンレス鋼表面上の微小き裂の深さおよび閉じ具合の定量評価

    巨 陽, 宮津 亨, 祖山 均

    日本実験力学会講演論文集　(3)　311-313　2003

    Publisher: 日本実験力学会

    ISSN： 1346-4922

  210. 336 疲労強度向上におけるキャビテーション・ショットレス・ピーニングとショット・ピーニングの比較(き裂の発生・進展の抑制,治癒)(破壊の発生・進展とその評価および抑制)(オーガナイスドセッション8)

    祖山 均, Macodiyo Dan Odhiambo, 坂 真澄

    学術講演会講演論文集　52　332-333　2003

    Publisher: 日本材料学会

  211. Cavitation erosion and surface modification using cavitation

    H Soyama

    JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS　48　(10)　814-820　2003

    ISSN： 0915-1168

  212. Effect of Nozzle Diameter of Low Speed Water Jet on Ability of Cavitating Jet in the Air

    SOYAMA Hitoshi, SAITO Kenich, SAKA Masumi

    2002　83-84　2002/09/06

    Publisher: The Japan Society of Mechanical Engineers

  213. Optimum Processing Time of Cavitation Shotless Peening for Aluminum Alloy

    SASAKI Kei, SOYAMA Hitoshi, SAKA Masumi

    2002　(37)　62-63　2002/03/16

    Publisher: The Japan Society of Mechanical Engineers

  214. Ability of Cavitating Jet in the Air

    SOYAMA Hitoshi, SAITO Kenichi, MIKOSHIBA Naoki, SAKA Masumi

    2002　(37)　76-77　2002/03/16

    Publisher: The Japan Society of Mechanical Engineers

  215. 気中キャビテーション噴流

    祖山 均

    超音波TECHNO　14　(3)　78-81　2002/03

  216. 220 気中キャビテーション噴流による金属材料への圧縮残留応力の導入

    祖山 均, 斎藤 建一, 御子柴 直樹, 佐々木 圭, 坂 真澄

    学術講演会講演論文集　51　223-224　2002

    Publisher: 日本材料学会

  217. 115 Surface Modification of Tool Alloy Steel SKD61 by Cavitation Shotless Peening

    SOYAMA Hitoshi, SASAKI Kei, SAKA Masumi

    The ... Manufacturing & Machine Tool Conference　2001　(3)　35-36　2001/11/20

    Publisher: The Japan Society of Mechanical Engineers

    More details Close

    Although cavitation impacts normally cause damage in hydraulic machinery, the impacts can strengthen metallic materials as same as shot peening (SP). In case of peening by cavitation impacts, the shots are not required, thus the peening is called "cavitation shotless peening (CSP)". In older to figure out the mechanism of the improvement of life time of forging die treated by CSP, residual stress and hardness were measured with and without CSP. Tested materials were tool alloy steel SKD61. It was revealed that the residual stress of the surface treated by CSP was more compressive than that of not peened specimen and still kept compressive after heat treatment.

  218. 超音波より強力 水だけで洗浄

    祖山 均

    超音波TECHNO　13　(11)　66-71　2001/11

    Publisher: 日本工業出版

    ISSN： 0916-2410

  219. 202 Attainment of Cavitating Jet in the Air

    SOYAMA Hitoshi, SAITO Kenichi

    Fluids engineering conference ...　2001　26-26　2001/09/28

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-2882

  220. 211 Improvement of Hardness of Carbon Steel Surface by Means of Arc Discharge in the Atmosphere

    SOYAMA Hitoshi, YOSHIDA Yosuke, SAKA Masumi

    2001　51-52　2001/09/21

    Publisher: The Japan Society of Mechanical Engineers

  221. キャビテーション噴流式壊食試験装置

    祖山 均

    ターボ機械　29　(4)　193-198　2001/04

    DOI： 10.11458/tsj1973.29.193 　

  222. 421 An Evaluation of Cavitation Shotless Peening by Using Almen Strip

    SOYAMA Hitoshi, KUMANO Hiroyuki, SAITO Kenichi, SAKA Masumi

    2001　(36)　164-165　2001/03/10

    Publisher: The Japan Society of Mechanical Engineers

  223. 422 A Monitoring Method for Surface Modification by Using a Cavitation Jet

    KUMANO Hiroyuki, SOYAMA Hitoshi, SAKA Masumi

    2001　(36)　166-167　2001/03/10

    Publisher: The Japan Society of Mechanical Engineers

  224. 423 A New Parameter on Resistance of Materials to Cavitation Impact

    SOYAMA Hitoshi, KUMANO Hiroyuki

    2001　(36)　168-169　2001/03/10

    Publisher: The Japan Society of Mechanical Engineers

  225. キャビテーション噴流式ハイブリッド表面改質装置の開発

    祖山 均

    油空圧技術　39　(10)　26-31　2000/10

  226. 602 Peening on Surface of Gear by Using a Cavitating Jet

    SOYAMA Hitoshi, SAKA Masumi, SATO Azuma

    2000　149-150　2000/08/15

    Publisher: The Japan Society of Mechanical Engineers

    More details Close

    Surface modification by using a cavitating jet is proposed in order to improve fatigue strength of silicon manganese steel, to introduce compressive residual stress into surface of metals, and to improve corrosion resistance of the carbon steel. Thus, the cavitating jet can be used for surface modification instead of shot peening. In case of the surface modification by using acavitating jet, it is possible to peen surface of materials without shots. It can be called "shotless peening". The great advantage of the shotless peening is that it is easy to peen the bottom of the gear tooth, since the shots do not stack between the tooth. In the present paper, in order to demonstrate peening of gear, the residual stress of the surface of the gear before and after exposing to a cavitating jet was measured by using an X-ray diffraction apparatus. The peening area was also measured by using a paintmethod.

  227. キャビテーション噴流による材料の表面改質

    祖山 均

    材料と環境　49　(6)　485-495　2000/06

    DOI： 10.3323/jcorr1991.49.332 　

  228. キャビテーション衝撃力計測装置の開発

    祖山 均

    オートメーション　45　(6)　88-93　2000/06

    Publisher: 日刊工業出版プロダクション

    ISSN： 0473-5587

  229. 気泡で表面改質

    祖山 均

    超音波TECHNO　12　(4)　42-45　2000/04

    Publisher: 日本工業出版

    ISSN： 0916-2410

  230. 306 Introduction of Backside Damage into Silicon Wafer by Using a Cavitation Jet

    KUMANO Hiroyuki, SOYAMA Hitoshi, SAKA Masumi

    2000　(35)　90-91　2000/03/11

    Publisher: The Japan Society of Mechanical Engineers

  231. 316 Effect of Water Quality on Improvement of Corrosion Resistance of Carbon Steel by Cavitating Jet

    SOYAMA Hitoshi, SATO Gaku, SAKA Masumi

    2000　(35)　110-111　2000/03/11

    Publisher: The Japan Society of Mechanical Engineers

  232. 507 Improvement of Fatigue Strength for Rotating Bending by Cavitating Jet

    SOYAMA Hitoshi, KUSAKA Takuya, SAKA Masumi

    2000　(35)　170-171　2000/03/11

    Publisher: The Japan Society of Mechanical Engineers

  233. 506 Optimization of Introducing Compressive Residual Stress by Peening

    SOYAMA Hitoshi, Sasaki Kei, SAKA Masumi

    2000　(35)　168-169　2000/03/11

    Publisher: The Japan Society of Mechanical Engineers

  234. キャビテーション噴流による表面改質

    祖山 均

    機械の研究　52　(1)　7-13　2000/01

    Publisher: 養賢堂

    ISSN： 0368-5713

  235. Surface modification of materials by using a cavitating jet

    Hitoshi Soyama

    Zairyo to Kankyo/ Corrosion Engineering　49　(6)　332-336　2000

    Publisher: Japan Soc of Corrosion Engineering

    DOI： 10.3323/jcorr1991.49.332 　

    ISSN： 0917-0480

  236. Remarkable Effects of Leading- and Trailing-Edge-Shapes on Violent Vibrations of Supercavitating Hydrofoils.

    Soyama Hitoshi, Naka Hironori, Abe Junpei, Miyakawa Takashi, Takahashi Makoto, Higuchi Jiro, Ikohagi Toshiaki, Oba Risaburo

    Reports of the Institute of Fluid Science, Tohoku University　11　47-52　1999/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  237. High-Speed Stereo-Observations of Highly Erosive Cavitating Flow-Pattern around a Typical Butterfly-Valve of Offset-Leaf-Type.

    Soyama Hitoshi, Iwasaki Masahiro, Takeda Sho, Hirata Yasushige, Higuchi Jiro, Oba Risaburo

    Reports of the Institute of Fluid Science, Tohoku University　11　61-68　1999/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  238. キャビテーション噴流による材料試験・表面改質における支配因子

    祖山 均

    噴流工学　15　(2)　31-37　1998/06

  239. キャビテ-ション噴流による表面改質

    祖山 均

    豊田研究報告　(51)　49-53　1998/05

    Publisher: 豊田理化学研究所

    ISSN： 0372-039X

  240. Inner-Flow-Visualizations of High-Speed Water-Jets Issued from a TypicalDiesel Nozzle at Several Injection Pressures

    Soyama Hitoshi, Uchida Toshihiko, Ito Yukio, Higuchi Jiro, Oba Risaburo

    Memoirs of the Institute of Fluid Science, Tohoku University　9　1-11　1998/03

    Publisher: Tohoku University

    ISSN： 0916-2860

  241. Material testing and surface modification by using cavitating jet

    Hitoshi Soyama

    Zairyo/Journal of the Society of Materials Science, Japan　47　(4)　381-387　1998

    Publisher: Society of Materials Science Japan

    DOI： 10.2472/jsms.47.381 　

    ISSN： 0514-5163

  242. The "Severe Erosion" Monitoring by Detecting Cavitation-Noise

    Soyama Hitoshi, Ito Yukio, Higuchi Jiro, Oba Risaburo

    Memoirs of the Institute of Fluid Science, Tohoku University　8　53-61　1997/03

    Publisher: Tohoku University

    ISSN： 0916-2860

  243. Behavior of Severe Cavitation Erosion Occurring in a High-Specific-Speed Centrifugal Pump due to Vibrations and Noise

    Soyama Hitoshi, Li S.R., Tonosaki Masashi, Uranishi Kazuo, Higuchi Jiro, Kato Hiroharu, Oba Risaburo

    Reports of the Institute of Fluid Science, Tohoku University　9　11-18　1997/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  244. Three Types of Vibrations on a Supercavitating Hydrofoil

    Soyama Hitoshi, Naka Hironori, Abe junpei, Miyakawa Takashi, Takahashi Makoto, Ikohagi Toshiaki, Oba Risaburo

    Reports of the Institute of Fluid Science, Tohoku University　9　19-24　1997/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  245. Jet structure analyses on high-speed submerged water jets through cavitation noises

    Y Adachi, H Soyama, Y Yamauchi, K Sato, T Ikohagi, R Oba

    JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING　39　(3)　568-574　1996/08

    DOI： 10.1299/jsmeb.39.568 　

    ISSN： 1340-8054

  246. Base-Vented Flow-Simulation near the Trailing Edge of Supercavitating Hydrofoils with Pseudo-Kirchhoff-Noses

    Oyama Makoto, Abe Junpei, Soyama Hitoshi, Oba Risaburo

    Memoirs of the Institute of Fluid Science, Tohoku University　7　135-145　1996/03

    Publisher: Tohoku University

    ISSN： 0916-2860

  247. Several Kinds Vibrations Arisen around a Typical Highspeed SupercavitatingHydrofoil with Various Nose Shapes

    Soyama Hitoshi, Naka Hironori, Miyakawa Takashi, Ikohagi Toshiaki, Abe Junpei, Kuwako Hiroshi, Oba Risaburo

    Reports of the Institute of Fluid Science, Tohoku University　8　1-12　1996/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  248. 高速度撮影に関する動向

    祖山 均, 川野 聡恭

    可視化情報　15　(57)　87-92　1995/04

    Publisher: The Visualization Society of Japan

    DOI： 10.3154/jvs.15.57_87 　

    ISSN： 0916-4731

  249. Singular Behavior of Erosion-Standoff-Distance-Curves for Highspeed-Water-Jets in Air

    Soyama Hitoshi, Yokota Motohiro, Shintani Masayuki, Uchida Toshihiro, Ikohagi Toshiaki, Oba Risaburo, Higuchi Jiro

    Reports of the Institute of Fluid Science, Tohoku University　7　35-45　1995/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  250. Behavior of Cavitation Nuclei in High-Speed Submerged Water-Jet-Tests

    Yamauchi Yoshiaki, Soyama Hitoshi, Adachi Yasunori, Ikohagi Toshiaki, Oba Risaburo, Hirata Yasushige

    Reports of the Institute of Fluid Science, Tohoku University　7　1-14　1995/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  251. SEM Observations on the Progress of Severe Cavitation Erosion Arisen in a Typical Centrifugal Pump

    Soyama Hitoshi, Ito Yukio, Ichioka Takehiko, Oba Risaburo, Kato Hiroharu, Ito Norio

    Reports of the Institute of Fluid Science, Tohoku University　7　57-68　1995/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  252. Several Aspects of Fatigue Failure Caused by Cavitation Erosion

    Hokkirigawa Kazuo, Soyama Hitoshi, Ahmed M. Shemy, Oba Risaburo, Watanabe Tsutomu

    Reports of the Institute of Fluid Science, Tohoku University　7　47-56　1995/03

    Publisher: Tohoku University

    ISSN： 0916-2879

  253. Base Vented Performance Simulation for Supercavitating Hydrofoils with Pseudo-Kirchhoff Noses Operating within the Subcabvitating Region"(共著)

    Makoto Ohyama, Junpei Abe, Yoshihiko Sunayama, Hitoshi Soyama, Masahiro Yamabe, Risaburo Oba

    JSME Int. J. , Ser. B　38　(2)　258-264　1995

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmeb.38.258 　

    ISSN： 1340-8054 1347-5371

    More details Close

    In order to clarify supercavitating hydrofoil performance numerically, especially in the base-vented state at a low incidence, we attempt to perform numerical simulations for three typical thin supercavitating hydrofoils with pseudo-Kirchhoff noses by means of the QUICK method. The precise water-tunnel tests on the supercavitating steady lift- and drag-performance for the foils are examined after the marked effects of leading edge and the peculiar behavior of disc drag have been clarified. The analyses agree well with the experiments, especially in the base-vented flow at low incidences, showing several interesting facts.

  254. High-Speed Stereo-Observations of Violent Vibrations Associated with Three Types of Cavitation (共著)

    Hironori Naka, Hitoshi Soyama, Kentaro Sakagami, Risaburo Oba, Masahiro Yamabe

    JSME Int. J. , Ser. B　38　(1)　66-72　1995

    Publisher: The Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmeb.38.66 　

    ISSN： 1340-8054 1347-5371

    More details Close

    In order to improve the reliability of high-speed hydraulic machinery, detailed behavior of the violent vibrations appearing on a typically low-drag Eppler foil is systematically observed by means of high-speed stereophotography. We can clearly observe the following three types of violent vibrations : (i) the vibrations resulting from a singly-attached cavity, usually arising at a higher incidence α_i, (ii) ones resulting from large travelling bubbles arising at a lower incidence, (iii) a mixture of these two types.

  255. 高速水中水噴流による顕著なピーニング効果(ステンレス鋼の残留応力改善)

    祖山 均, 山内 由章, 井小萩 利明, 大場 利三郎, 佐藤 一教, 進藤 丈典, 大島 亮一郎

    噴流工学　12　(2)　13-22　1995

  256. Marked Peening Effects by Highspeed Submerged-Water-Jets (Residual Stress Change on SUS304)

    祖山 均, 山内 由章, 井小萩 利明, 大場 利三郎, 佐藤 一教, 進藤 丈典, 大島 亮一郎

    J.Jet Flow Engineering　12　(2)　13-22　1995

  257. 高速水噴流のメカニズムとその有効利用

    祖山 均, 佐藤 一教

    日本機械学会誌　96　(9)　847-847　1993/09

    Publisher: 一般社団法人日本機械学会

    ISSN： 0021-4728

Show all ︎Show first 5

Books and Other Publications 10

  1. 金属疲労とショットピーニング 改訂第4版

    ショットピーニング技術協会

    大河出版　2018/09

  2. Measurement and Instrumentation

    高偉, 清水裕樹, 羽根一博, 祖山均, 足立幸志

    朝倉書店　2017/03/25

    ISBN: 9784254201659

  3. バイオマス由来の高機能材料

    舩岡正光, 祖山均, 木村悟隆, 山口健, 柴田圭, 堀切川一男ほ

    エヌ・ティー・エス　2016/11/23

  4. 新版キャビテ-ション -基礎と最近の進歩-

    加藤洋治, 藤川重雄, 松本洋一郎, 高比良裕之, 右近良孝, 神山新一, 上條謙二郎, 山口一, 中武一明, 井小萩利明, 大島明, 岡田庸敬, 服部修次, 祖山均 ほか

    森北出版　2016/06/30

    ISBN: 9784627602397

  5. 水素利用技術集成 Vol. 4

    岡野一清, 井関孝弥, 阿部竜, 児玉竜也, 郷右近展之, 中村優美子, 伊藤直次, 市川貴之, 高野俊夫, 池田哲史, 秋葉悦男, 笠井秀明, 中西寛, Wilson Agerico Dino, 三浦良雄, 佐原亮二, 水関博志, Marcel H, F. Sluiter, 大野かおる, 川添良幸, 星野公三, 高野則之, 横堀壽光, 大見敏仁, 祖山均, 高桑脩, 亀川厚則, 岡田益男, 佐藤正志, 久慈俊郎, 島隆則, 侯召民, 池田一貴, 高木成幸, 大友季哉, 折茂慎一, 西宮伸幸, 駒口健治, 菅原武, 庄野厚, 斉藤泰和, 藤田健一, 山口良平, 伊藤靖彦, 井上博史, 大平勝秀, 李海文, 経済産業省商務流通保安グループ高圧ガス保安室

    株式会社エヌ・ティー・エス　2014/04/25

    ISBN: 9784864690829

  6. Advanced Experimental and Numerical Techniques for Cavitation Erosion Prediction

    G. L. Chahine, J. P. Franc, A. Karimi, G. Bark, R. E. Bensow, P. F. Pelz, T. Keil, G. Ludwig, M. Dular, S. Hattori, S. Nishimura, O. Takakuwa, H. Soyama, M. Fukaya, S. J. Schmidt, M. S. Mihatsch, M. Thalhamer, N. A. Adams, C. T. Hsiao, R. Raju, E. Johnsen

    Springer　2014

    ISBN: 9789401785389

  7. Strength Design Handbook for Failure Prevention of Products

    服部 敏雄, 川田 宏之, 田川 哲哉, 東郷 敬一郎, 中井 善一, 三浦 英生, 足立 幸志, 祖山 均ほか

    株式会社エヌ・ティー・エス　2012/02/14

  8. 機械工学便覧基礎編α4流体工学

    井小萩利明, 井上雅弘, 亀本喬司, 辻裕, 新美智秀, 深野徹, 松本洋一郎, 望月修, 祖山均ほか

    日本機械学会　2006/01/20

  9. Fatigue and Shot Peening

    廣瀬正吉, 青木勇, 稲川哲雄, 梅村貢, 飯田喜介, 佐野雄二, 祖山均,ほか

    2004/02

  10. 新版キャビテ-ション -基礎と最近の進歩-

    加藤洋治, 藤川重雄, 松本洋一郎, 高比良裕之, 右近良孝, 神山新一, 上條謙二郎, 山口一, 中武一明, 井小萩利明, 大島明, 岡田庸敬, 服部修次, 祖山均 ほか

    槇書店　1999/10/20

    ISBN: 4837506585

Show all Show first 5

Presentations 62

  1. X-ray high-speed imaging of hydrodynamic cavitation and biomass particle passing through Venturi tube

    H. Soyama, X. Liang, K. Kajiwara, W. Yashiro

    Fluid dynamics meets synchrotron X-ray high-speed imaging

  2. Mechanical Surface Treatment of Additive Manufactured Ti6Al4V by Cavitation Peening International-presentation Invited

    Hitoshi Soyama

    2020 Spring International Conf. on Material Sciences and Technology (MST-S)　2020/08/15

  3. Fundamentals and applications of cavitation peening comparing with shot peening and laser peening International-presentation Invited

    Hitoshi SOYAMA

    International Conference on Advanced Surface Enhancement 2019　2019/09/10

  4. Improvement of Fatigue Strength of Light Metals by Mechanical Surface Treatment International-presentation Invited

    Hitoshi SOYAMA

    International Conference on Light Alloys and Metal Materials (LAMM 2019)　2019/08/21

  5. Observation of Cavitation around a Submerged Fan Jet International-presentation Invited

    Hitoshi SOYAMA

    The 12th Pacific Rim International Conference on Water Jet Technology　2019/08/08

  6. Improvement of Fatigue Strength of Additive Manufactured Metals by Solid-Liquid-Gas Interfacial Phenomena Induced by Pulse Laser International-presentation Invited

    Hitoshi Soyama

    International Conference on Advanced Material Research and Processing Technology (AMRPT2019)　2019/07/20

  7. Mechanical Surface Treatment of Additive Manufactured Metallic Material by Solid-Liquid-Gas Interfacial Phenomena Induced by Pulse Laser International-presentation Invited

    Hitoshi Soyama

    International Conference on Materials Research & Nanotechnology　2019/06/12

  8. Strength of Titanium Alloy 6Al4V Manufactured by the Electron Beam Powder Bed Melting (EBPB) Additive Manufacturing (AM) Method International-presentation

    Daniel G. Sanders, Hitoshi Soyama

    AEROMAT2019　2019/05/07

  9. Solid-Liquid-Gas Interfacial Phenomena and Its Practical Application for Mechanical Surface Treatment : Cavitation Erosion and Cavitation Peening International-presentation Invited

    Hitoshi Soyama

    3rd International Symposium of Cavitationand Multiphase Flow (ISCM2019)　2019/04/20

  10. Surface Mechanics Design by Cavitation Peening Using Submerged Pulse Laser International-presentation

    Hitoshi Soyama

    7th International Conference on Laser Peening and Related Phenomena　2018/06/21

  11. Improvement of Wear Resistance of Steel by Means of a Cavitating Jet and a Submerged Pulse Laser International-presentation

    Hitoshi Soyama, Mitsuru Sato

    10th International Symposium on Cavitation (CAV2018)　2018/05/15

  12. Introduction of Compressive Residual Stress into Alloy Tool Steel by Submerged Laser Peening Utilizing Laser Cavitation Impact International-presentation

    Hitoshi Soyama

    9th International Conference on Leading Edge Manufacturing in 21st Century (LEM21)　2017/11/14

  13. Introduction of Compressive Residual Stress into Alloy Steel by Cavitation Peening Using Laser Cavitation International-presentation

    Hitoshi Soyama

    13th International Conference on Shot Peening　2017/09/19

  14. Surface Mechanics Design of Metallic Materials by Cavitation Peening International-presentation

    Hitoshi Soyama

    11th International Conference on Advanced Materials and Processing　2017/09/07

  15. Opposed cavitating jets and their application for cavitation peening of wall surrounding hole International-presentation

    H. Soyama

    23rd International Conference on Water Jetting　2016/11/14

  16. Effect of Bubble Collapse Impact on Submerged Laser Peening International-presentation

    H. Soyama

    The 6th International Conference on Laser Peening and Related Phenomena　2016/11/07

  17. Improvement of Fatigue Life of Welded Parts by Cavitation Peening and Water Jet Peening International-presentation

    11th Pacific Rim International Conference on Water Jet Technology　2016/10/16

  18. Spectroscopy Analysis of Laser Abrasion and Laser Cavitation Induced by Pulse Laser International-presentation

    20th International Conference on Condensed Matter Nuclear Science (ICCF20)　2016/10/03

  19. Using In-Situ Resources for 3D manufacturing on Mars International-presentation

    NASA Cross Industry Innovation Summit　2016/09/20

  20. Mechanical Surface Treatment of Duralumin Plate by Bubble Induced by Pulse Laser International-presentation

    9th International Symposium on Cavitation　2015/12/06

  21. Mechanical Surface Treatment of Duralumin by Laser Cavitation International-presentation

    1st International Workshop on Cavitation Peening and Related Phenomena　2015/10/27

  22. Experimental Formula to Estimate Aggressive Intensity of a Cavitating Jet for Cavitation Peening International-presentation

    ASME-JSME-KSME Joint Fluids Engineering Conference 2015　2015/07/27

  23. Surface Mechanics Design by Cavitation Peening International-presentation

    The 5th International Conference on Laser Peening and Related Phenomena　2015/05/10

  24. Reduction of hydrogen embrittlement cracking of stainless steel SUS316L by cavitation peening International-presentation

    O. Takakuwa

    APCFS/SIF-2014 (Asian-Pacific Conference on Fracture and Strength, International Conference on Structural Integrity and Failure)　2014/12/09

  25. Improvement of Threshold Stress Intensity Factor Range of Stainless Steel by Cavitation Peening International-presentation

    12th International Conference on Shot Peening　2014/09/15

  26. Improvement of fatigue strength of duralumin plate with a hole by a cavitating jet International-presentation

    22nd International Conference on Water Jetting　2014/09/03

  27. Surface Modification Using Chemical and Physical Effects at Cavitation Bubble Collapse International-presentation

    International Symposium for the 70th Anniversary of the Tohoku Branch Chemical Society of Japan　2013/09/28

  28. Effect of Nozzle Outlet Geometry of a High-Speed Water Jet on Cutting Ability of Submerged Abrasive Water Jet International-presentation

    10th Pacific Rim International Conference on Water Jet Technology　2013/04/25

  29. Power Law of Injection Pressure and Nozzle Diameter on Aggressive Intensity of a Cavitating Jet International-presentation

    21th International Conference on Water Jetting　2012/09/19

    More details Close

    Effect of Nozzle Shape for High Injection Pressure on Aggressivity of Cavitating Jet. [Proceedings of 21st International Conference on Water Jetting, (2012), 367-378] H. Soyama, O. Takakuwa and A. Naito

  30. Effect of Dissolve Gas on Luminescent Spots Induced by a Cavitating Jet International-presentation

    8th International Symposium on Cavitation　2012/08/13

  31. Optimum Injection Pressure of a Cavitating Jet on Introduction of Compressive Residual Stress into Stainless Steel International-presentation

    Kazuya Nagasaka, Osamu Takakuwa, Akima Naito

    19th International Conference on Nuclear Engineering　2011/10/24

  32. Fundamental and Applications of Cavitation Peening International-presentation

    The 3rd International Conference on Laser Peening and Related Phenomena　2011/10/11

  33. Comparison of Effects of LSP, UNSM and Cavitetion Peening on Residual Stress, Microstructure and Local Mechanical Properties of 316 Stainless Steel, Ti64, IN718 SPF alloys International-presentation

    A. Gill, Y. Zhao, J. Guenes, Y. Pyun, H. Soyama, S. R. Mannava, D. Quian, V. K. Vasudevan

    The 3rd International Conference on Laser Peening and Related Phenomena　2011/10/11

  34. Effect of Injection Pressure and Size of Nozzle Throat of a Cavitating Jet on Cavitation Peening International-presentation

    O. Takakuwa, A. Naito

    11th International Conference on Shot Peening　2011/09/12

  35. Luminescent Spots Induced by a Cavitating Jet International-presentation

    ASME-JSME-KSME Joint Fluids Engineering　2011/07/24

  36. 流動キャビテーションにおけるラジカル反応

    キャビテーションに関するシンポジウム（第15回）　2010/11/22

  37. Chemical Reactor Using Radical Induced by a Cavitating Jet International-presentation

    T. Muraoka

    20th International Conference on Water Jetting　2010/10/20

  38. Enhancement of Aggressivity of Cavitating Jet and Its Practical Application International-presentation

    International Conference on Jets, Wakes and Separated Flows　2010/09/27

  39. Comparison of Abilities of Various Cavitating Jets International-presentation

    K. Nishizawa, M. Mikami

    9th Pacific Rim International Conference on Water Jetting Technology　2009/11/20

  40. Enhancement of Cavitation Aggressivity around a Cavitating Jet by Injecting Low-Speed Water Jet for Cavitation Peening International-presentation

    K. Nishizawa, M. Mikami

    7th International Symposium on Cavitation　2009/08/17

  41. Release of Micro Strain in Tool Alloy Steel by a Cavitating Jet in Air International-presentation

    Nao YAMADA, Osamu TAKAKUWA, Yuichi SEKINE, Mitushiro MIKAMI

    19th International Conference on Water Jetting　2008/10/15

  42. Singularity of Cavitation Shotless Peening Compared with Shot Peening International-presentation

    10th International Conference on Shot Peening　2008/09/14

  43. 群列キャビテーションによる材料の表面改質

    化学系学協会東北大会　2007/09/21

  44. Introduction of Macro-Strain with Releasing Micro-Strain by Cavitation Shotless Peening International-presentation

    6th International Symposium on Impact Engineering　2007/09/16

  45. 気中キャビテーション噴流による表面改質

    日本混相流学会年会講演会　2007/06/22

  46. Cavitation Shotless Peening International-presentation

    6th MFN Asian Shot Peening Workshop　2006/11/13

  47. Surface Modification by Using a Cavitating Jet International-presentation

    The 8th Pacific Rim International Conference on Water Jet Technology　2006/10/10

  48. キャビテーション・ショットレス・ピーニングによる金属材料の強度向上

    日本保全学会第３回学術講演会　2006/07/06

  49. Cavitation Peening by Using Cavitating Jet in Air International-presentation

    K. Homma

    9th International Conference on Shot Peening　2005/09/06

  50. Cavitating Jet in Air Using Multiple Nozzle International-presentation

    M.Mikami

    2005 Amerian Waterjet Conference　2005/08/21

  51. キャビテーション・ショットレス・ピーニングによる金属表面改質

    軽金属学会第75回シンポジウム　2004/10/14

  52. Improvement of Fatigue Strength by Using a Cavitating Jet in Air International-presentation

    M.Mikami, K.Homma

    17th International Conference on Water Jetting　2004/09/07

  53. キャビテーションの新しい利用－表面改質への有効利用

    第12回キャビテーションに関するシンポジウム　2004/03/18

  54. Peen Forming by Using a Cavitating Jet in Air International-presentation

    K.Saito

    7th Pacific Rim International Conference on Water Jetting Technology　2003/10/27

  55. Cavitation Shotless Peening for Improvement of Fatigue Strength International-presentation

    D.Odhiambo, K.Saito

    8th International Conference on Shot Peening　2002/09/16

  56. Suitable Waiting Operation of an MC-Centrifugal- Slurry-Pump International-presentation

    Symposium on Cavitation and Gas-Liquid Flow in Fluid Machinery and Devices　1995/08/13

    More details Close

    (プロシーディング) Cavitation and Gas-Liquid Flow in Fluid Machinery and Devices ASME 1995 143 149

  57. Visualization of Vortex-and Cloud-Cavitation around a Submerged Water-Jet by Stereoscopic Stacking Display of Digital Images International-presentation

    Symposium on Flow Visualization and Image Processing of Multiphase System　1995/08/13

    More details Close

    (プロシーディング) Flow Visualization and Image Processing of Multiphase System ASME 1995 43 48

  58. Flow Visualization International-presentation

    Symposium on Flow Visualization and Image Processing of Multiphase System　1995/08/13

    More details Close

    (プロシーディング) Flow Visualization and Image Processing of Multiphase System ASME 1995

  59. Vibrations and Noises Associated with Severe Cavitation Erosion Arisen in a High-Specific-Speed Centrifugal-Pump International-presentation

    International Symposium on Cavitation　1995/05/02

    More details Close

    (プロシーディング) Proceddings of the International Symposium on Cavitation DCN Bassin 1995 225 232

  60. ターボ機械のキャビテーション

    第８回フレッシュマンセミナー「ポンプ・送風機設計の基礎」　1993/08/27

    More details Close

    (プロシーディング) ポンプ・送風機設計の基礎 日本工業出版 1993 1 12

  61. 激しい壊食の音響検出法

    第７回キャビテーションに関する会議　1992/10/13

    More details Close

    (プロシーディング) 第７回キャビテーションに関する会議講演論文集 日本学術会議 1992 125 126

  62. High-Speed Observations of Highly Erosive Vortex- Cavitation Arisen in a Centrifugal Pump International-presentation

    International Symposium on Cavitation and Erosion in hydraulic structures and Machinery　1992/05/26

    More details Close

    (プロシーディング) Cavitation and Erosion in Hydraulic Structures and Machinery Hohai University 1992 45 50

Show all Show first 5

Industrial Property Rights 30

  1. 平面曲げ疲労試験機

    祖山均, 古澤達哉

    Property Type: Patent

  2. 金属短線の洗浄装置および金属短線の洗浄方法

    千葉秀輝, 増田雅芳, 宮崎幸一, 三浦俊範, 祖山均

    5900961

    Property Type: Patent

  3. キャビテーション噴流能力推定方法、キャビテーション噴流能力推定システム、及びキャビテーション噴流能力推定装置、並びにキャビテーション噴流推定誤差算出方法、及びキャビテーション噴流推定誤差算出装置、並びにキャビテーション噴流能力評価方法、及びキャビテーション噴流能力評価装置、キャビテーション噴流能力算出式特定システム、及びキャビテーション噴流能力算出式特定装置、並びにコンピュータに実行させるためのプログラム及び同プログラムを記録したコンピュータ読み取り可能な記録媒体

    祖山 均

    Property Type: Patent

  4. ウォータージェット噴射ノズル，ウォータージェット噴射装置，ウォータージェットを用いた洗浄方法および胃壁洗浄装置

    祖山均, 阿美克典, 山本松男

    Property Type: Patent

  5. 口腔洗浄装置および口腔洗浄方法

    祖山均, 山本松男, 滝口尚

    Property Type: Patent

  6. キャビテーション発生装置

    祖山均, 三上光弘, 菊池務, 志賀啓介

    5578318

    Property Type: Patent

  7. 耐水素脆化特性に優れた金属材料の製造方法および耐水素脆化特性に優れた金属材料

    祖山均, 高桑脩

    Property Type: Patent

  8. エロージョンモニタリング手法

    庄子哲雄, 竹田陽一, 祖山 均

    Property Type: Patent

  9. 水噴流によるピーニング方法及び装置

    祖山 均

    5540375

    Property Type: Patent

  10. 炭化水素製造方法および炭化水素製造装置

    祖山均

    Property Type: Patent

  11. 振動による表面改質の評価方法ならびに装置

    祖山均, 甲斐彰, 関根裕一

    Property Type: Patent

  12. 応力保持装置およびX線回折装置

    祖山 均, 甲斐 彰, 高桑 脩

    5515036

    Property Type: Patent

  13. トラクションドライブおよびその表面処理方法

    東崎康嘉, 吉見壮司, 園部浩之, 塩津勇, 酒井賢治, 祖山均

    4969325

    Property Type: Patent

  14. CVTベルト用エレメントの表面処理方法

    志水政紀, 服部勇仁, 小林大介, 荒川一哉, 祖山均, 長沢裕二, 西澤博幸, 大澤正敏

    5078071

    Property Type: Patent

  15. キャビテーション壊食量予測方法及び予測システム

    有働 竜二郎, 深谷 征史, 原田 一郎, 小野 滋義, 祖山 均

    4812100

    Property Type: Patent

  16. 動植物の育成方法及び動植物の育成装置

    祖山 均

    Property Type: Patent

  17. 管内部の表面改質または洗浄方法及び該方法に使用される管内部の表面改質または洗浄装置

    祖山 均

    4635206

    Property Type: Patent

  18. 金属材料や半導体材料等の表面改質法とそのための表面改質装置と，加工能力の高いキャビテーション・ショットレス・ピーニング法

    祖山 均

    5066703

    Property Type: Patent

  19. 核破砕中性子源水銀ターゲット容器のその場診断システム

    二川正敏, 勅使河原誠, 粉川広行, 池田裕二郎, 祖山 均, 吉田信俊

    Property Type: Patent

  20. 電磁式衝撃加力によるキャビテーション発生装置、その装置による材料の損傷評価試験方法、及び材料の表面改質方法

    二川正敏, 粉川 広行, 池田 裕二郎, 祖山 均, 伊達 秀文, 万場 猛

    Property Type: Patent

  21. 金属部品等の表面改質および洗浄方法およびその装置

    祖山 均

    4240972

    Property Type: Patent

  22. 機械部品等の表面処理および洗浄方法ならびにそれらの装置

    Property Type: Patent

  23. 材料固有のキャビテーション衝撃力のしきい値特定方法と，キャビテーション噴流による壊食量の定量的予測法と，そのための壊食量の定量的予測装置

    祖山 均

    4665186

    Property Type: Patent

  24. キャビテーション噴流による材料試験装置の液体圧力制御方法，液体槽内圧力制御機構，噴射圧力制御機構，液体槽内圧力および／または噴射圧力の自動制御機構

    特許第3921514号

    Property Type: Patent

  25. 金属被加工物表面のキャビテーションによる耐食処理法およびキャビテーション浸食の低減方法およびキャビテーション浸食防止法を向上させる加工処理をした加工物

    Property Type: Patent

  26. 金属部品等の表面改質および洗浄方法およびその装置(Surface Refining Method of Metal Part, Washing Method and Device)

    Property Type: Patent

  27. 裏面にキャビテーションゲッタリングサイトを有する半導体ウエーハと，当該半導体ウエーハの製造方法と，当該半導体ウエーハによるゲッタリング方法

    Property Type: Patent

  28. キャビテーションによる耐食処理法(Corrosion Resistant Processing Method by Cavitation)

    Property Type: Patent

  29. 水中水噴流を利用する加工方法(Processing Method Utilizing Underwater High-Speed Water Jet))

    2878529

    Property Type: Patent

  30. 流体機械の翼(Vane for Fluid Machine)

    2954308

    Property Type: Patent

Show all Show first 5

Research Projects 40

  1. Surface Mechanics Design Competitive

    2012/04 - Present

  2. Study on Residual Stress Competitive

    System: Grant-in-Aid for Scientific Research

    2002/04 - Present

  3. Cavitation Erosion Competitive

    System: Grant-in-Aid for Scientific Research

    1991/04 - Present

  4. Surface modification by Using Cavitating Jet Competitive

    System: Grant-in-Aid for Scientific Research

    1991/04 - Present

  5. 固気液混相を用いたエネルギーの時間的・空間的凝縮と3D-Metalの疲労強度向上への展開

    祖山 均

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 基盤研究(B)

    Category: 基盤研究(B)

    Institution: 東北大学

    2023/04/01 - 2026/03/31

  6. 治療抵抗性口腔疾患に対する革新的抗炎症療法の確立

    齋藤 正寛, 八幡 祥生, 田中 志典, 祖山 均

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 挑戦的研究(萌芽)

    Institution: 東北大学

    2021/07/09 - 2024/03/31

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    近年口腔と全身疾患に関して多くの因果関係が明らかにされており、循環器疾患、自己免疫疾患、内分泌疾患などの全身疾患により産生が亢進される炎症性サイトカインやリンパ循環を介した炎症性細胞の循環が口腔内炎症の遷延に寄与していると指摘されている。特にヒト最大の免疫組織である腸管免疫の破綻により発症する炎症性腸疾患（IBD)は、腸のみならず全身の免疫機構の低下を招き、口腔内でも根尖性歯周炎、歯周炎等の口腔内炎症性疾患のハイリスクになることが知られており口腔と全身疾患を繋ぐ臓器炎症ネットワークに注目が集まっている。 本年度は既に当研究室で確立した炎症腸疾患に根尖性歯周炎（AP)を発症させるIBD-APモデルを用いて、腸炎による顎骨破壊増悪化機構の解析を実施した。IBDによる体重減少、腸粘膜上皮の破壊、腸管の狭小及び短縮化が観察された。IBD-APを観察すると、AP単独と比較して顎骨内で形成される病変が拡大することが観察された。この結果よりIBDは顎骨における炎症性破壊を増悪化する可能性が示されたため、RNA-seq解析で分析を行った。その結果、IBDを発症することで顎骨内で既に炎症反応が起きており、IBD-APになると白血球の活性化、リンパ球浸潤に伴う炎症マーカーの発現上昇が確認された。組織解析を行うと、IBDを発症した顎骨内で既に根尖部の歯周組織の破壊が観察され、さらにIBD-APになると病変内に壊死細胞を中心にその周囲に炎症系細胞の浸潤を伴う病変が根尖部顎骨内に形成されていた。根管内のドラッグデリバリーシステムの開発を行うため、ラットAPモデルに着手し、顎骨破壊を伴う根尖部病変の形成を確認した。

  7. Research on novel functional materials by hydrodynamic cavitation containing particles Competitive

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2020/04 - 2023/03

  8. Elucidation of solid-liquid-gas interfacial phenomena induced by pulse laser and its practical application

    Soyama Hitoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

    Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

    Institution: Tohoku University

    2018/10 - 2022/03

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    The purpose of this study is to elucidate the solid-gas-liquid interface phenomenon that occurs when a pulsed laser is applied to a metal surface placed in water, and then applied for mechanical surface treatment. In this study, it was focused on the laser cavitation which is produced after laser ablation. In laser peening, it is thought that the impact force due to laser ablation is utilized, and there was no interest in laser cavitation, but the principal investigator found that the impact force due to laser cavitation is greater than that due to laser ablation. The improvement of fatigue strength of metal materials by surface modification using laser cavitation was demonstrated.

  9. Surface Mechanics Design Using Laser Cavitation and Its Practical Application for 3D Additive Manufacturing Material

    Soyama Hitoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2017/04 - 2020/03

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    When the surface of a metallic material placed in water was irradiated with a pulsed laser, ablation and bubble, i.e., laser cavitation were generated. In present study, laser cavitation was investigated and it was utilized for mechanical surface modification utilizing the impact force generated at bubble collapse. In normal underwater laser peening, the impact force by ablation is used. In this study, the impact force at laser cavitation collapse was enhanced by optimizing the processing conditions, and it was applied to a titanium alloy by additive manufacturing, and the fatigue strength of the titanium alloy improved 2 times. It was also demonstrated that this mechanical surface modification can improve fatigue strength to the same level or more with less than half the energy of conventional water film laser peening and less than half the pulse density.

  10. Enhancement of Interface Chemical Reaction in Bubble Jet and Control of Water Purification Process using Sun Light and Nano Pulsed Discharge

    NISHIYAMA Hideya, SOYAMA Hitoshi, YASUOKA Koichi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: Tohoku University

    2014/04/01 - 2018/03/31

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    A nobel reactive plasma device for water purification was developed successfully by utilizing a single or two capillary discharges with sudden expansion diameter. It aims at the establishment of decomposition of persistand organic pollutants with high energy efficiency and control of water purification process. The correlation between discharge characteristics and generated bubble hehavior in the cappillaries, flow pattern, pump performance, and decolorization characteristics of methylene blue were experimentally clarified each other. The time dependent 2D diffusion model for oxidized radicals in the nano pulsed discharged bubble and treated solution outside bubble was successfully established. The optimum operating condition for high OH radical concentration in the solution was clarified by comparing with experimental data to obtain the high energy efficiency.

  11. High effective strengthening of metallic implants made of metals with self-tunable elastic modulus by partial deformation

    NAKAI Masaaki, SOYAMA Hitoshi, ISHIMOTO Takuya, NARITA Kengo

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    2015/04/01 - 2017/03/31

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    The metals with self-tunable elastic modulus exhibit low elastic moduli before deformation, and their elastic moduli increase during deformation by deformation-induced phase transformation. In this study, we tried to achieve both low elastic modulus and high durability using these metals deformed partially at the position where high strength is required. In order to deform only at the surface of the metals, peening treatment was employed. As the results, the durability of the metals was increased significantly by the peening treatment in comparison with that of the other metals without deformation-induced phase transformation. According to the microstructure observation, deformation-induced ω phase was observed only near the surface of the specimens after the peening treatment. Therefore, it is possible to increase the durability without increase in elastic modulus by partial deformation for these metals.

  12. New material creation following biomineralization - Challenge to control lime scale -

    Soyama Hitoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    Institution: Tohoku University

    2015/04/01 - 2017/03/31

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    In order to generate calcium carbonate applicable to structural materials that follow biomineralization such as shell and crustaceans, mechanical properties of materials produced by biomineralization such as shell and crab were investigated, and production of calcium carbonate by laser was tried inspiring by lime scale such as water scale. It was revealed that many shells were aragonite, the exterior shell and the scallops were calcite, that the yield stress of aragonite was about 1 GPa and the yield stress of calcite was about 400 MPa using an inverse analysis of an indentation test. It was also demonstrated that calcium carbonate could be generated by irradiating a laser beam to a test specimen placed in the aqueous calcium hydrogen carbonate solution.

  13. Development of predictive maintenance scheme for fatigue cracks based on dissipated energy measurement

    Sakagami Takahide, YUDATE Yukihiko

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Kobe University

    2014/04/01 - 2017/03/31

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    Development of the predictive maintenance scheme was investigated for structural integrity assessment, in which fatigue crack initiation and propagation in the structural members were evaluated from in-situ measurement results of the actually applied stress distribution and the dissipated energy emission. Scientific interpretation of the prediction of fatigue crack initiation and the estimation of fatigue limit was studied by investigating the mechanism of energy dissipation during fatigue damage evolution process. Further the thermoelastic stress analyses was applied for on-site measurement of stress distributions around fatigue cracks, and the future crack propagation behavior was estimated by the fracture mechanics approach. The technique was applied to estimate fatigue crack propagation rate and to evaluate the effectiveness of repair or reinforcement for defective portions in steel structures.

  14. Research on Hybrid Peening and Its Application for Suppression of Hydrogen Embrittlement

    SOYAMA Hitoshi, IGA Yuka, TAKAKUWA Osamu, AOYAGI Yoshiteru

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2012/04/01 - 2015/03/31

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    In order to suppress of hydrogen embrittlement of metallic materials, which is an obstacle to realize hydrogen society, “hybrid peening” was established. Here, “hybrid peening” means a mechanical surface treatment which combined with different peening method such cavitation peening, laser peening and shot peening. In the present research, suppression of hydrogen embrittlement of chrome molybdenum steel and stainless steel by the peening was demonstrated by experimentally. It was also revealed that the peening reduced invention of hydrogen into metallic materials by introducing compressive residual stress into the materials and the peening suppressed the hydrogen embrittlement of the metallic materials.

  15. Investigation of mechano-luminescence of rocks and its possibility of earthquake prediction

    SOYAMA Hitoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    Institution: Tohoku University

    2011 - 2012

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    Mechano-luminescence of rocks induced by friction test and tensile test was evaluated. It was observed that the concluded that luminescence intensity of the rocks with large containing quartz was more intense and the peak at 370 nm which corresponds to the second positive band of nitrogen was observed by the rock in nitrogen gas. It was concluded that the mechano-luminescence of rocks was induced by piezoelectric effect and plasma of ambient gas.

  16. New Functional Layer Produced by Cavitation Shotless Peening

    SOYAMA Hitoshi, NISHIKAWA Masaaki, CHIBA Akihiko, JU Yang

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: Tohoku University

    2008 - 2010

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    A surface modification using cavitation impact, which was called cavitation shotless peening, CSP, was proposed. Improvements of yield stress, fatigue strength, wear and hydrogen embrittlement by CSP were proofed, with introducing compressive residual stress and releasing micro strain.

  17. Nano-Crystallization by Using Cavitation Shotless Peening

    SOYAMA Hitoshi, WATANABE Yutaka, YAMANAKA Masashi, KAI Akira

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2005 - 2006

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    The main results obtained are as follows: 1. Cavitation impact was increased by increases of injection pressure of cavitating jet and an ambient pressure at cavitation bubble collapsing region. Novel cavitation shotless peening, which use a cavitating jet in water with associated water jet, was proposed and it was revealed that the ability of the jet was increased. 2. In order to make clear a mechanism of improvement of fatigue strength by cavitation shotless peening, residual stress was precisely measured by using an X-ray diffraction method. It was revealed that residual stress was closely related to the improvement of fatigue strength by cavitation shotless peening. 3. A fundamental parameter approach was tried to evaluate grain size and micro strain. It was revealed that the fundamental parameter approach can evaluate them. It was found that cavitation shotless peening relieved micro strain with introducing macro strain, i.e., compressive residual stress. 4. It was revealed that plastic deformation depth, elastic deformation depth and maximum deformation depth could evaluate the characteristics of the surface treated by cavitation shotless peening using indentation test. 5. In order to make clear the mechanism of gettering using cavitation shotless peening, the gettering site of silicon wafer was observed by using a transmitting electron microscope, the gettering site was consist of the dislocations whose size was about 100 nm. 6. Cavitation impact was increased by changing nozzle outlet geometry, the peening effect was increased, and then the improvement of fatigue strength was also increased. It was revealed at treatment of gear teeth that the consideration of flow pattern at mechanical parts of cavitation shotless peening was very important.

  18. レーザビームの電気光学偏光によるマイクロ波影像装置の開発

    巨 陽, 村岡 幹夫, 祖山 均

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 萌芽研究

    Institution: 東北大学

    2004 - 2005

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    本研究は,被検査体を透過したマイクロ波ビームの電場分布を電気光学結晶に入力されたレーザビームの偏光に置き換えることによりマイクロ波影像を得る装置を開発し,被検査体の電磁物性分布を画像化することを目的とするものである。高分解能なマイクロ波影像をリアルタイムで取得可能な装置の開発,さらにその応用としてシリコンウェーハの導電率分布の非接触計測への実用化を図る。2年継続により,(I)マイクロ波影像装置の開発,(II)マイクロ波周波数及び電気光学結晶の最適化,(III)シリコンウェーハの導電率分布の定量評価,なる3項目の研究を推進し,目標を達成する。本年度は以下の実績を得た。 1.マイクロ波周波数及び電気光学結晶の最適化 マイクロ波周波数,及び電気光学結晶の種類を変化させ,それぞれにおけるマイクロ波影像を得ることにより,マイクロ波影像装置におけるマイクロ波周波数,及び電気光学結晶の種別の影響を調べ,最適化を行った。これにより,高分解能,高感度の影像を実現した。 2.シリコンウェーハの導電率分布の定量評価 上記の研究成果を踏まえ,マイクロ波影像装置の応用例として,シリコンウェーハの導電率分布の非接触計測を実施した。種々の加工条件により導電率分布の違うシリコンウェーハ試験片を用いて,試験片を透過したマイクロ波の電場分布をマイクロ波影像装置により測定し,試験片の導電率分布によって変化するマイクロ波の応答を計測した。さらにマイクロ波の応答と従来の接触型測定法により評価される試験片の導電率から,マイクロ波による導電率の定量評価式を生成し,シリコンウェーハの導電率分布の非接触リアルタイム計測を実現した。

  19. ひずみを活用した亜酸化銅太陽電池の高性能化

    祖山 均, 巨 陽

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 萌芽研究

    Institution: 東北大学

    2004 - 2005

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    本研究は,半導体にひずみを付与すると電気的特性が変化することを活用し,半導体の一種である亜酸化銅太陽電池を取り上げ,ひずみの付与による太陽エネルギを電気エネルギへ変換する変換効率を向上させて亜酸化銅太陽電池を高性能化することを目的とする。本年度は初年度の研究を発展させ、ひずみを活用した亜酸化銅太陽電池の高性能化を図った。 1.光起電力効果におけるひずみの影響の定量的評価 銅板を高温酸化させて亜酸化銅を銅板上に生成させた試験片を作製し,それを片持ちはりとして荷重-変位を測定し,亜酸化銅の縦弾性係数を求めた。また酸化条件を変化させた亜酸化銅のひずみを,2次元検出器を有するX線回折装置を使用して2D法により,求めた縦弾性係数を用いて亜酸化銅の残留ひずみを評価した。その結果,酸化条件により残留ひずみが異なることを明らかにした。また亜酸化銅太陽電池に曲げ応力や垂直応力を与えることにより,光起電力が向上することを明らかにし,求めた縦弾性係数により,亜酸化銅に負荷した応力をひずみに換算して評価した。 2.光起電力効果におけるひずみの影響の電気的特性の評価 銅板から生成した亜酸化銅太陽電池について太陽電池シミュレータにより光起電力を計測しながら,ひずみを付与して,ひずみにより光起電力が向上することを明らかにした。また亜酸化銅太陽電池にひずみを付与しながら亜酸化銅太陽電池の抵抗などを計測した結果,ひずみによる光起電力向上には,亜酸化銅太陽電池のショットキー障壁が変化している可能性を明らかにした。 3.ひずみを活用した亜酸化銅太陽電池の高性能化 亜酸化銅を酸化する際の酸化時間や酸素分圧により光起電力が異なることを明らかにし,最適酸化条件を得た。また亜酸化銅太陽電池に曲げ応力を負荷するよりも垂直応力を負荷したほうが亜酸化銅太陽電池を高性能化できることを明らかにした。

  20. Study of Next Cavitation Shotless Peening

    SOYAMA Hitoshi, WATANABE Yutaka, YAMANAKA Masashi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2002 - 2004

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    The main results obtained are as follows : 1.The cavitating jet in air was observed and it was revealed that the periodical cavitation-cloud-shedding around the high-speed water jet and the fluctuation of the low-speed water jet were interfered each other. 2.Pure aluminum specimen was treated by the cavitation shotless peening. It was revealed by means of recrystallization-etch technique that the plastic deformation was induced by the cavitation shotless peening. 3.The cavitation impacts energy was measured by the cavitation impact counter. It was revealed that the cavitation impacts induced by the cavitating jet in air were more intense compared with that of the cavitating jet in water. 4.The stress distribution of cavitation impacts was estimated by the shape of plastic deformation pits. In order to apply the cavitation shotless peening to tribology area, the introduction of compressive residual stress into titanium alloy was revealed. 5.In order to establish monitoring method of cavitation shotless peening, the relation between the impact energy measured by the PVDF sensor and the vibration measured by the laser doppler velocity meter were revealed. 6.The proposed shotless peening and the conventional shot peening were compared. The difference of the peening methods in view point of introduction of compressive residual and the improvement of fatigue strength was revealed. 7.In order to control the cavitation impact intensity, the plastic deformation pits produced by cavitation shotless peening were measured precisely. The pressure distribution of cavitation impact was successfully controlled by the injection pressure of the low-speed water jet and the standoff distance. 8.The injection pressure of the low-speed water jet and the standoff distance, which were the main parameters of the cavitation shotless peening, were optimized.

  21. Development of THz Wave Tomography Technique and Nondestructive Evaluation of Delamination in Mounted Electronic Packages

    JU Yang, SAKA Masumi, SOYAMA Hitoshi, SASAGAWA Kazuhiko, OGURA Yukio

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2002 - 2003

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    1.Development of the generation and detection system of THz wave A pulsed laser beam generated by a fs laser was separated into a pump and a probe beam by a beam splitter. The pump beam was then focused on a nondoped GaAs wafer. Due to the photoconductive effect, a pulsed THz beam was generated from the GaAs emitter. Moreover, the THz beam was focused on a ZnTe crystal white the probe beam was also focused on the ZnTe sensor, through a time delay. Due to the Pockels effect, a phase variation of the probe beam was induced by the electro-optic modulation. By using a pair of balanced photodiodes, the phase variation which varies with the electric field of the THz wave was detected. 2.Construction of the tomography system The generated THz beam was focused on the inspected sample, and the reflected THz wave which carries the information of the sample was focused on the ZnTe sensor. The probe beam was synchronized with the reflected THz beam at the ZnTe sensor. In the same time, the sample was moved in the x and y direction by an electric stage. Therefore, by adjusting the time delay as a time gate, the amplitude of the reflected THz wave from a cross section of the sample was recorded, and a tomograph was generated. 3.Nondestructive evaluation of delamination in electronic packages For the practical use of the THz wave tomography, the generation of the 3D image of delamination between the chip and the encapsulant resin in the mounted electronic packages, and the establishment of nondestructive evaluation method of mounted electronic packages on an assembly line, are being promoted.

  22. 活性酸素の高耐食性不動態被膜生成への有効利用

    祖山 均, 渡辺 豊

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 萌芽研究

    Institution: 東北大学

    2002 - 2003

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    本研究は,一般には流体機械に振動や騒音、致命的損傷を生じる害悪であるキャビテーション気泡の崩壊時に生じる局所的高圧かつ高温環境下を用いて,キャビテーション噴流が活性酸素を生成することを実証し,この活性酸素の高耐食性不動態被膜生成への有効利用を目的とする。本年度は,昨年度の成果を踏まえて以下の研究を実施した。 1.活性酸素生成を目的としたキャビテーション噴流の最適化 キャビテーション気泡の崩壊衝撃力の計測等により,キャビテーション噴流の最適噴射条件を明らかにした。キャビテーション噴流をシリコンウェーハ裏面に噴射して生成させた酸化積層欠陥により,ゲッタリング効果があることを実証した。さらにキャビテーション噴流により加工して酸化積層欠陥を生じる場合には,X線回折によりシリコンの結晶構造が乱れていること,ならびにWrightエッチングによりエッチピットを生じる、ことを明らかにした。 2.活性酸素による耐食性不動態被膜生成の最適化 生成した金属酸化物の酸化被膜が生じる光電効果において,ある一定のひずみを付与することにより,短絡電流が増大して,光起電力が増大する事実を明らかにした。なおこのときには開放電圧はほとんどひずみの影響を受けなかった。しかしながら,この一定値以上のひずみを負荷すると,短絡電流ならびに開放電圧ともに低下して,光起電力が著しく低下することが判明した。すなわち,ひずみによる金属酸化物半導体の光起電力向上においては最適値が存在することが判明した。

  23. Development of Shotless Peening System and Manufacturing Considering Preservation of Environment

    SOYAMA Hitoshi, KOBAYASHI Yuji, YAMANAKA Masashi, WATANABE Yutaka

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2001 - 2003

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    1.The cavitating jet in air was successfully realized using cavitation shotless peening system without a water-filled chamber. It was revealed that the cavitating jet in air was most powerful compared with a cavitating jet in water and a normal water jet in air. 2.The erosion test and measurement of cavitation intensity were carried out at various conditions to measure the ability of cavitating jet in air, then the optimum condition of the cavitating jet was obtained. 3.Several steel were peened by the cavitating jet in air, the residual stress was measured by an X-ray diffraction method. The introduction of compressive residual stress was demonstrated. It shows the possibility of the surface modification by using the cavitating jet in air. 4.The optimum peening time was obtained from the relation of the peening time and the residual stress or the fatigue test at constant load changing with the peening time. 5.In order to compare the proposed shotless peening considering the prevention of environment and the conventional shot peening, a rotating bending fatigue test was carried out, and it was shown that the improvement of fatigue strength by shotless peening was better than that of shot peening. 6.In order to establish non-destructive testing method to evaluate the surface modification layer peened by the shotless peening, the residual stress and austenitic ratio were measured by using an X-ray diffraction method. 7.The improvement of fatigue strength of gear was demonstrated by a bending fatigue test of gear tooth comparing the result of shot peening. 8.In order to apply the shotless peening to various materials, the relation between the cavitation intensity and the materials properties was investigated, and the fundamental threshold level of materials for the cavitation impact was revealed.

  24. Development of a Millimeter-Wave Imaging Compact System & Contaceless and Quantitative Evaluation of Delamination and Crack with High Spatial Resolution

    SAKA Masumi, YAMAMOTO Hiroshi, YANG Ju, SOYAMA Hitoshi, AKAMATSU Satoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2001 - 2002

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    1. Development of a compact imaging system Usually, network analyzer is used as the equipment for microwave nondestructive testing. However, network analyzer has lager size and its price is high. Hence it becomes difficult to use it in the industrial environment. Therefore, a millimeter-wave compact equipment was developed to overcome these problems. Both the amplitude and the phase measurement can well be carried out by the compact equipment. 2. Development of a millimeter-wave reflection focusing sensor A millimeter-wave focusing sensor utilizing two ellipsoidal reflectors woo developed for nondestructive evaluation of materials. By using the focusing sensor, liftoff distance between the sensor and sample woo effectively enlarged, while a higher spatial resolution was also obtained. 3. Detection of defects and evaluation of electrical characteristics in electronic devices and thin films with high spatial resolution The delamination, which may occur between the chip pad and the encapsulate resin in IC packages, was inspected by millimeter-wave imaging technique. The full and part delamimations were successfully detected. Also a method for contactless measurement of the conductivity of thin conducting films, such us Indium Tin Oxide film, was developed. The measurement was successfully carried out by using the millimeter-wave compact equipment. 4. Quantitative evaluation of closed small cracks on the metal surface A dual frequency technique was developed to evaluate the depth of small 2-D cracks of which situation regarding crack closure is unknown. On the other hand, a method to evaluate closure stress of cracks was developed. The effect of closure stress on the dual frequency technique was evaluated. In addition, to evaluate 3-D cracks, from the modified dual frequency equation, a new component named interference waveform was introduced, by which the shape and size of small 3-D cracks were successfully evaluated.

  25. Responses of Angle-Beam Ultrasonic Shear Waves to Closed Cracks and Highly Sensitive Quantitative Nondestructive Evaluation of Crack Sizes Together With Closure Stresses

    SAKA Masumi, KAMIYA Shoji, SOYAMA Hitoshi, MIHARA Tsuyoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2000 - 2001

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    1. Clarification of angle-beam shear wave responses to closed cracks and its mechanism Specimens containing two-dimensional (2D) fatigue cracks with different crack depths and closing stresses were prepared, and the cracks situated vertically on the specimen back-wall were inspected. The beam angle for achieving considerable sensitivity in shear wave response for a wide range of cracks was estimated as 50°. 2. Construction of theoretical model of angle-beam shear wave response to closed crack By taking care of the shape of the response curve that contains the simultaneous information of crack depth and closing stress, the model of angle-beam shear wave response has been proposed. 3. Evaluation of crack size and closing stress by inverse analysis (1) Verification for small two-dimensional closed cracks A relation between the amplitude of the crack echo and the crack depth for open cracks was determined. Then, another relation between the reflection coefficient, which is defined by the ratio of echo-height of closed, crack to that of open crack, and crack closure stress was obtained. Finally, by using the model of closed crack response constructed in the previous section 2, which contains these relations, the values of crack closure stress and crack depth of an unknown 2D crack have been determined by solving an inverse problem. (2) Extension to shallow three-dimensional closed cracks The methodology of evaluating 2D closed crack was extended to shallow 3D closed crack. Since a small segment of length of a 3D shallow crack can be approximated as a segment of 2D crack, the inverse analysis for the response measured at the center of each segment was individually performed. (3) Verification for shallow three-dimensional closed cracks Crack closure stress and the crack tip contour of a 3D closed crack were determined by the technique developed in the above section (2).

  26. Research on Hybrid Surface Modification by Cavitating Jet

    SOYAMA Hitoshi, WATANABE Yutaka, SAKA Masumi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    1999 - 2001

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    1. Injecting a cavitating jet to metallic materials such as stainless steel, silicon manganese steel, tool alloy and carbon steel, it was revealed that the cavitating jet can introduce compressive residual stress on the metallic materials by means of X-ray diffraction method. It was also revealed to evaluate the surface modification with depth from the surface by using Micro-Vickers hardness testing changing with the load. 2. It was revealed that the corrosion resistance and the mechanical strength of carbon steel were improved at same time, i.e., hybrid surface modification, by using a cavitating jet. 3. The flow rate of various type of nozzle was measured. The cylindrical nozzle was suitable for the cavitating jet for the hybrid surface modification in view point of repeatability. 4. Cavitation impacts were measured by a PVDF transducer, which is developed by the investigators, for various cavitating conditions. The intensity of cavitation impact can be controlled by the upstream and downstream pressure of the nozzle. 5. It was shown that the cavitating jet could improve the fatigue strength of aluminum alloy casting, silicon manganese steel and carbonized steel. 6. Cavitating flow was affected by the shape of impinging surface. In order to treat gear, the optimum peening condition was investigated. It was revealed that the peened surface by a cavitating jet was very smooth comparing with that of the shot peening. 7. It was shown that the roughness of the surface and the residual stress were main factor of optimum processing time. It will be possible to evaluate the surface modification by means of the residual stress using X-ray diffraction method.

  27. ショットレス・ピーニングによる表面改質法確立のための企画調査

    祖山 均, 清水 誠二, 服部 修次, 山中 将, 太田 訓郎, 高野 義夫

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(C)

    Institution: 東北大学

    2000 - 2000

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    本研究では、機械材料を高強度化する表面改質法についてショット・ピーニングの知見を踏まえて、鋼球などのショットを用いない次世代表面改質法を日本から世界に向けて発信するために、キャビテーション、ウォータジェット、レーザ等によるショットレス・ピーニング法および同法の応用の可能性について調査を行った。 1.種々の手法別・適用例別の調査 ショットレス・ピーニングの手法として、キャビテーション、ウォータジェット、レーザによる方法を取り上げ、ショット・ピーニングと比較検討しながら、各手法の特徴を調査した。その結果、原子力プラントの保全技術や航空機部品の表面改質質に、ショット・ピーニング、キャビテーション噴流、ウォータジェット、レーザが用いられていることが明らかになった。またキャビテーション噴流による鍛造用金型の表面改質の有効性を呈示した。 2.学問的分類による調査 キャビテーションによるピーニングを取り上げて、回転曲げ疲労試験によりショット・ピーニングと疲労強度を比較検討した結果、同様に疲労強度を向上できること、表面粗さの増大が極めて少ないことを明らかにした。 3.ショットレス・ピーニングの現状技術の把握 レーザによるピーニングは加工コストがショット・ピーニングの約10倍であること、ウォータジェットを用いる場合には高圧プランジャポンプが高価であるために初期コストが高いこと、それに対し、キャビテーション噴流を用いる場合にはキャビテーション気泡の崩壊衝撃力を有効利用するので低コストで表面改質を施工できる利点が明らかになった。

  28. シリコンウェハ表面の高純度化へのキャビテーションの有効利用

    祖山 均

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 奨励研究(A)

    Institution: 東北大学

    1999 - 2000

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    本研究は,シリコンウェハ裏面に加工歪層を付与して半導体デバイスプロセス中に生じる不純物をウェハ表面から除去するゲッタリングが半導体プロセスにおいて必要不可欠であり,かつ従来のSiO_2粒子を用いたサンドブラストでは粒子の汚染が問題となることを踏まえて,キャビテーション噴流まわりのキャビテーション気泡の崩壊衝撃力によるゲッタリング法の確立を目的とし,キャビテーション噴流によるゲッタリング効果の実証のために以下の研究を実施した。 1.ゲッタリング効果の定量的評価 キャビテーション噴流式試験装置を使用して,ゲッタリングサイトとなる酸化積層欠陥OSFを生成するためにシリコンウェハに加工ひずみ層を与え,そのひずみ量をX線回折式応力測定装置により定量的に評価した。一般に用いられているX線応力測定装置は多結晶材料を計測対象とし,シリコンウェハのような単結晶材料のひずみや応力は計測できない。そこで,加工ひずみ層と未加工部分で計測した回折角のシフト量を,シリコンウェハに応力を負荷して校正する方法を試みた。 2.最適ゲッタリング条件の確立 初年度はキャビテーション噴流用ノズルおよびシリコンウェハを固定してシリコンウェハに加工ひずみ層を導入していた。本年度は,本ゲッタリング法の実用化を目的として,シリコンウェハの全面を加工できるように,ノズルを走査した場合にゲッタリングサイトとなる酸化積層欠陥を導入するための最適加工速度を明らかにした。

  29. Development of a Microwave Focusing Sensor and a High Resolution Imaging System for Nondestructive Evaluation of Materials

    SAKA Masumi, SASAGAWA Kazuhiko, SOYAMA Hitoshi, KAMIYA Shoji, TAKEUCHI Masahiro, YANG Ju

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B).

    Institution: Tohoku University

    1999 - 2000

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    1.Clarification of the principles of microwave focusing and reflecting by using electromagnetic wave theory A focusing sensor was developed. The microwave reflection occurring at the interface of the materials, in a small area, was analyzed. The characteristic of the microwave response relative to the size and the shape of defects, and their electromagnetic properties was clarified. 2.Evaluation of delaminations with a high spatial resolution The delaminations between the lead frame and the encapsulant resin in IC packages were evaluated. The variations of the amplitude and the phase of the reflection coefficient, for the samples with and without delaminations, were observed. The parameters used for evaluation of the delamination in a high spatial resolution were obtained. 3.Development of the microwave imagine system The microwave sensor was used to scan the detected object in two perpendicular directions in a plane parallel to the object. A high speed imaging system was developed, where information of the defects was recorded corresponding to the measurement position. 4.Improvement of the focusing sensor For increasing the spatial resolution, the shape and the set position of the focusing sensor were optimized. The spatial resolution was further increased while a larger standoff distance between the sensor and the detected object was remained. 5.Microwave applications in evaluation of the thickness of films and coating materials and the state of the interface between the coating materials and their substrates A new method for evaluation of the conductive film, which has widely been used in the manufacture of liquid crystal and solar cell etc., was investigated. Moreover, the capability of microwave to detect a small crack in the silicon film, which is used to make solar cells, was also confirmed. 6.Development of the compact imagine system Based on the developed imaging system, the compact imaging system was designed fundamentally, which is expected to be used for large machines and structures in the industrial environment. A new scanning sensor was suggested for realizing the small size, low cost and popular imaging system.

  30. Research on Surface Modification System by Using a Cavitating Jet

    SOYAMA Hitoshi, URANISHI Kazuo, WATANABE Yutaka, ITO Takatoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B).

    Institution: Tohoku University

    1998 - 2000

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    1.Surface modification system has been developed considering scale effects of nozzle diameter. Diameter of nozzle is from 0.4mm to 1.9mm. 2.Cavitation impacts were measured by a PVDF transducer for various cavitating conditions. When the nozzle diameter was increased, the frequencies of the cavitation impacts were not only increased but also the intensity of the cavitation impacts increased. Reducing air contents ration in the test water also increased the cavitation impacts. 3.Optimum peening time or optimum scanning speed was demonstrated by measuring hardness or residual stress. The cavitating jet can introduced compressive residual stress in the surface of the materials. The value of the compression was saturated at certain processing time or speed. In case of the improvement of the corrosion resistance by using a cavitating jet, optimum processing time was obtained by the relation between the potential by means of an electrochemical method and the processing time. 4.Regarding test liquid of the cavitating jet, several liquids ware tested changing with pH.Suitable test liquids for iron were clarified referring Pourbaix diagram of iron. 5.Peening for gears and specimens with a notch was carried out. It was revealed that the peened surface by a cavitating jet was very smooth comparing with that of the shot peening. The cavitating jet can also introduce the compressive residual stress into hard materials such as tool alloy SKD61. 6.In order to demonstrate improvement of fatigue strength by suing a cavitating jet, a rotating bending fatigue test was carried out. It was shown that the cavitating jet could improve the fatigue strength. It was also revealed that the cavitating jet could improve the corrosion resistance about 30% by means of an electrochemical method.

  31. Development of Ultrasonic Angle Beam Technique of Quantitative Nondestructive Evaluation of Small Closed Cracks

    SAKA Masumi, KAMIYA Shoji, SOYAMA Hitoshi, MIHARA Tsuyoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: TOHOKU UNIVERSITY

    1998 - 1999

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    The main results obtained are as follows : 1. Clarification of mechanism to enhance the sensitivity of ultrasonic inspection of closed cracks using the ultrasonic angle beam technique A new evaluation approach, namely the optimum incidence method, has been developed, which provides the way to deal with sensitivity to the smaller cracks, specially the closely ones. It has been verified experimentally by using both fully open and tightly closed 2-D cracks that the evaluation sensitivity can be enhanced significantly when the beam is directed with a small angle of incidence, θィイD2iィエD2 【similar or equal】 2 deg., the response of which is characterized by the nearly antisymmetric variation in amplitude of the back-wall echo signal around the position of the crack. 2. Establishment of theoretical modeling of ultrasonic angle beam response for the evaluation of small closed cracks For 2-D fatigue cracks having depth of 0.5〜5.0 mm, we have developed method for sizing their depths together with the information of crack closure, by solving an inverse problem on a personal computer. The evaluation method has been extended for plates having different thickness and also for different materials, where it has been found that the evaluation sensitivity is enhanced significantly for the case of thinner plates. 3. Extension of the evaluation method to small 3-D closed cracks The evaluation method developed above has well been extended to small 3-D closed cracks. 4. Verification of the method by using small closed 3-D surface cracks We have verified that the method can be successfully applied for the evaluation of depths of small 3-D closed cracks together with the information of their crack closure.

  32. キャビテーション噴流による機械材料表面への高耐食性不動態層生成

    祖山 均

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 奨励研究(A)

    Institution: 東北大学

    1997 - 1998

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    本研究は,通常流体機械に損傷をもたらすキャビテーションを,キャビテーション噴流を用いて制御して機械材料表面に直接的に耐食性不動態層を生成して,その不動態層を定量的に評価することを目的としている。本年度は,平成9年度の研究成果を踏まえて,耐食性不動態層の生成および評価について以下の研究を実施した。 1. 耐食性不動態層の評価 耐食性不動態層の程度を示す物理量として,イオン交換水中での腐食電位を用いることを見出し,キャビテーション噴流にさらした試験片の耐食性を評価した。また試験片表面をカラーフィルムで光学顕微鏡撮影し,そのネガから設備備品費で購入したフォトスキャナによりデータを入力して画像処理し,耐食性向上を評価した。 2. 最適加工条件の確立 キャビテーション噴流による耐食性不動態層の生成に及ぼす因子の把握および,最適加工条件の確立を目的として,種々の条件のキャビテーション噴流を炭素鋼表面に噴射して不動態層を生成し,上記のイオン交換水中の腐食電位を耐食性を表す指標として,不動態層の耐食性を評価した。その結果,不動態層は,キャビテーション係数(ノズル下流側圧力とノズル下流側圧力の比),スタンドオフ距離(ノズルと被加工面までの距離),被加工面上での噴流軸中心からの距離,噴射時間などにより変化し,それぞれ最適値が存在することを明らかにした。また設備備品費で購入した純水用電気伝導率計を用いて水質をモニタし,水質の影響も調べた。メカノケミカル的な観点から,キャビテーション衝撃力を自作したセンサにより計測して,衝撃力と耐食性向上の関係を明らかにし,残留応力の計測も行った。

  33. キャビテーション噴流によるアモルファス層の直接的生成

    祖山 均

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 奨励研究(A)

    Institution: 東北大学

    1996 - 1996

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    キャビテーション噴流によりアモルファス層を機械材料表面に直接生成することにより,材料の強度および耐食性の改善を目的として,キャビテーション噴流による表面改質の実験的研究を行った。得られた成果を以下に示す。 (1)キャビテーション噴流による機械材料の表面改質 キャビテーション噴流発生装置を用いて,備品費で購入のキャビテーション噴流制御装置により,噴流の吐出し圧力および周囲圧力を測定・制御して,ステンレス鋼や炭素鋼などの機械材料にキャビテーション噴流を噴射して,機械材料の表面改質を行った。キャビテーション流れの詳細な計測と機械材料表面の計測により,キャビテーション噴流による表面改質の最適加工距離を明らかにした。 (2)電気化学的計測法を用いたキャビテーション噴流による防食効果の実証 キャビテーション噴流にさらした炭素鋼試験片の腐食電位を計測した結果,キャビテーションにさらすと腐食電位が卑にシフトすることが判明した。また,分極を測定した結果,腐食電流が低下,すなわち,腐食速度が低下することが明らかになり,キャビテーション噴流により耐食性を向上させる表面改質が可能であることが実証された。 (3)X線解析法を用いたキャビテーション噴流による残留応力の改善の実証 キャビテーション噴流を噴射したステンレス鋼および炭素鋼試験片の残留応力をX線回折法を用いて計測し,引張り残留応力が緩和されることを実証した。

  34. Study on Cavitation Erosion Mechanism and its Prediction

    KATO Hiroharu, RETAILLEAU A, DOREY J.M, LECOFFRE Y, WOILLEZ J, LAVIGNE S, REBOUD J.L, FRANC J.P, MICHEL J.M, FUJIKAWA Shigeo, HATTORI Shuji, IWAI Yoshiro, SOYAMA Hitoshi, IKOHAGI Toshiaki, YAMAGUCHI Hazime, MATSUMOTO Youichiro

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for international Scientific Research

    Institution: University of Tokyo

    1995 - 1996

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    The main objective of this two year program is research on mechanism of cavitation erosion and its prediction. Impact force caused by collapsing cavity bubble is a key property and the measurement is desirable mostly both for research of the mechanism and for the prediction. Two members stayd two months in 1995 and 1996 at IMG,Grenoble for cooperative research experiments on the reliability and the accuracy of sensors. Two types of piezo sensors (piezo ceramic and PVDF) and a new sensor of MgO crystal were tested in a vortex cavitation erosion testing facility, named Cavermod. The gain of the three sensors agreed very well among them and it was confirmed that those sensors can be used as standard. The following researches were made by the members of the present program. 1. Numerical analysis of cloud cavitation and impinging vortex cavitation. 2. Estimation of impact pressure distribution by analysing measured pit shapes on metal surface. 3. Prediction of erosion intensity on prototype from pit counting of model assuming Strouhal similarity and water-hammer effect. 4. Prediction of erosion intensity from measured impact force distribution. 5. Proposal of a scenario for prediction of impact force distribution without experiment. 6. Effect of fluid properties such as acoustic impedance, surface tension, viscosity, on erosion.

  35. Development of Suitable Nozzle for Peening by High-Speed Submerged Water Jet

    IKOHAGI Toshiaki, SATO Kazunori, SOYAMA Hitoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Developmental Scientific Research (B)

    Institution: Tohoku University

    1994 - 1995

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    Our purpose is to establish a new peening technology using high-speed submerged water jets as an effective utilization of cavitation erosion energy. The structure and unsteady behavior of such water jets governing the processing ability have been investigated, and the peening effect has been verified experimentally. The research results are 1. The residual stresses of stainless steel specimens were measured by X-ray stress analizer. It is found that such peening effects as the stress improvement from pre-processing tensile conditions to compressible ones are realized definitely without any surface damage. 2. Cavitation noise and impulsive pressure were measured under a wide range of processing ambient pressure, and an exponential law between the acoustic power/the ambient pressure and the erosion rate is found to hold on the processing operation. 3. The breakup frequency of unsteady cavitation cloud which is related directly to the jet processing ability becomes maximum near the 1st peak of erosion curve, and an erosion mechanism is due to the intermittent impingement of water column. Also, the cylindrical nozzle provides a high breakup frequency and the most erosive action to the specimen surface. 4. Such a knowledge concerning jet processing is obtained that the impulsive pressures measured on various cylindrical surfaces distribute widely upto the back surface of the cylinder due to flow acceleration when the jet width is greater than the radius of curvature. 5. A computational code newly developed based on a model of compressible gas-liquid two-phase media can predict well the shock wave behavior in cavitation clouds and the cloud-breakup phenomenon.

  36. 渦による流体振動の効果的制御に関する研究

    祖山 均

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 奨励研究(A)

    Institution: 東北大学

    1993 - 1993

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    流体機械におけるエネルギー損失の低減化および振動・騒音の抑制を目的として、音響励起による流体振動の制御を試みるために、まず、物体まわりの流れパターンをキャビテーション気泡法により可視化して最高記録速度40,500コマ毎秒のハイスピードビデオカメラ等により、水中噴射流やバタフライ弁・翼形まわりの流れを詳細に観察し、また、翼形まわりの流れについては数値シュミレーションも行って流れパターンを把握し、次に、水中に種々の音波を発信して流れパターンの変化を観察した。その結果、以下のようなことが明らかになった。 1.キャビテーションを伴う高速水中水噴流では、高壊食性キャビテーション気泡雲が周期的に放出され、その放出周波数は吐出し圧力が大きくなるほど小さくなり、その周波数は数kHzのオーダである。バタフライ弁のまわりの高壊食性渦キャビテーションは、バタフライ弁から周期的に放出される渦キャビテーションが数多く合体して生じる。翼形まわりの揚力・抗力変動は、翼型背面に生ずる渦流れに起因し、抗力の大きさおよびその非定常特性は、特に後縁形状に依存している。 2.水中音波発生装置を用いて水中に音波を発信し、発信源から1mの位置で最大約130dBの音圧を得ることができることを確認した。特別に加工した水中音波反射板を用いて、約20cm離れた位置に音波を集中すると、最大215dBの音圧が得られるが、なお、発信源に超小型水中マイクロホンを使用しているために、音圧が発信周波数に依存する。 3.高速水中水噴流を種々の波形を持つ種々の周波数により励起したところ、気泡雲の放出周波数と同オーダの水中音波を発信すると、気泡雲の放出周波数が励起した音波の周波数に影響される。

  37. A Trial Manufacture of valves, which work safety in an extreme flow condition

    OBA Risaburo, ISHIGE Tadashi, SOYAMA Hitoshi, SATO Keiichi, ITO Yukio, IKOHAGI Toshiaki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Developmental Scientific Research (B)

    Institution: Tohoku University

    1992 - 1993

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    In order to make high reliability valves, which work safety in extreme flow conditions, we systematically observed the flow pattern and precisely measure the cavitation damage arisen around the butterfly-valve, the gate-slot and the hollow-jet-valve. In our study, we tool up the butterfly valve, because the butterfly valves are inexpensive, quite simple in construction, and can control the flow rate smoothly. We observed the flow pattern around a model of the butterfly-valve and measure the cavitation-induced-pressure-pulses by means of a pressure sensitive film and a hydrophone. The obtained results are summarized as follows : 1. As a result of the observation of the flow pattern around the butterfly valves by means of a highspeed video camera, whose maximum framing rate is 40, 500 frames per second, the erosion on the surface of the downstream-pipe is closely related to the singular longitudinal vortex cavitation associated the high shear region between the orifice jet and the recirculating region. The vortex cavitation develops into the severely erosive cavitation in the recirculating region with combining the several vortex cavitations. 2. The above-mentioned cavitation is weak as the projection is set on the orifice-side-surface of the butterfly valve, because the orifice jet becomes weak to be disturbed. We also make clear the cavitation-impulsive-pressures by means of the pressure sensitive film, and the cavitation noises by means of a hydrophone. 3. In the case of the eccentric butterfly valve, in which it is very convenient to change the valve washer, there are two types on the setting to the flow direction, namely the convex part sets on the upstream or the downstream to the valve stem. It is shown that there is no difference on the flow rates between the two types of the setting.

  38. A Study on Ultra-Highspeed Micro-Flow

    OBA Risaburo, SOYAMA Hitoshi, IKOHAGI Toshiaki, ESASHI Masanobu, KATO Koji

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for General Scientific Research (A)

    Institution: Tohoku University

    1992 - 1993

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    In order to make clear the flow characteristics and the dynamics in the ultra-highspeed micro-flow, we examined the cavitation characteristics of the ultra-highspeed flow. Then, we systematically observed the flow pattern in the nozzle and near the nozzle-outlet as well as the cavitating jet in a narrow watercourse, and also tried to simulate the cavitating flow numerically. The obtained results are summarized as follows : 1. We tested the ultra-pure water, whose resistance rate is more than 18 MOMEGA/cm. And, we made clear that the relative air content rates of the water, which is an important factor on the cavitation inception and develops, are considerably higher than that of tap-and still water. Then we made a special facility to degas the air within the ultra-pure water by using a special filtering membrane in order to avoid polluting the ultra-pure water, and we got the special ultra-pure water, whose relative air content rates are less than 0.2. 2. In order to make clear the flow pattern of ultra highspeed flow systematically, we carried out the observation and the erosion test on ultra highspeed water jets in the air and in the water. In the case of the jets in the water, it is shown that the jets are periodically shedding the cavitation bubble clouds. And also the erosion intensity is closely related to the cavitation bubble clouds. 3. The above-mentioned the erosion characteristics induced by the cavitation around the submerged highspeed water jets are systematically examined, the submerged water jets are very useful for cleaning and peening. Since the cavitation-impulse-pressures at the bubble collapsing can be effectively used on the cleaning and the peening, in the case of the submerged water jets. And also the suitable injection condition is shown for several nozzles. 4. In order to clarify the ultra highspeed flow pattern in a narrow watercourse, the cavitating jet in a narrow watercourse is carefully observed by means of a highspeed video camera, whose maximum framing rate is 40,500 frames per second and a digital image processing technique. The cavitation bubble clouds in the narrow watercourse are periodically shedding as same as the above-mentioned cavitation clouds associated with severely erosive cavitation.

  39. Analogy Between Cavitation Development and Solid Fracture Process Evaluated by AE Method

    ITO Yukio, NARASAKA Tsutomu, SOYAMA Hitoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for General Scientific Research (C)

    1990 - 1992

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    In order to study the analogy between cavitation development and solid fracture processes, the number of AE pulses and the pulse-height distributions were measured by means of acoustic emission AE method, both in the cavitating flow past a fence and in tensile deformation of mild steel, with respect to cavitation aspects and stress-strain relation. The results are summarized as follows ; (1) Cavitation process from the subcavitation state to the super-cavitation state is very similar to the solid fracture process, since both the number of AE pulses - cavitation number curve and the number - stress curve have two peaks in the critical state of the cavitation process and the fracture process. (2) The AE signal at the 1st peaks in the highly cavitation number and the stress regions, is the successive burst-type, while the isolated burst-type signal takes place at the 2nd peaks in the lower cavitation number and stress regions. This fact suggests the similarity between them. (3) The exponents calculated from the pulse-height distributions show the normal distribution near the inception and the end of the yield point. This fact is available to evaluate the analogy both processes.

  40. アコースティック・エミッションAE法によるキャビテーション壊食機構の解明

    祖山 均

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 奨励研究(特別研究員)

    Institution: 東北大学

    1989 - 1990

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Works 1

  1. Evaluation of cavitation impact energy

    2000/05/17 -

    Type: Software

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    2013/07/02 -

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    太陽熱発電と太陽光発電－さびで作った太陽電池－ 吉田小学校での出前授業

  38. 出前講座東北活性研ユニバーサイエンス（国際情報高等学校）

    2013/06/20 -

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    専門分野の概要，大学での学習・研究の状況，具体的な学習内容等の説明と講演

  39. テークスG、東北大の共同開発 荷重制御型平面曲げ式疲労試験機 表面改質層の亀裂発生・亀裂進展の評価が可能に

    2013/05/19 -

  40. 東北大学イノベーションフェア2013

    2013/01/17 -

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    東北大学イノベーションフェア2013に「キャビテーションテクノロジーの新展開」を出展した。

  41. 出前授業（会津学鳳高校）

    2012/10/05 -

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    専門分野の概要，大学での学習・研究の状況，具体的な学習内容等の説明と講演

  42. 楽しい理科のはなし2012 不思議の箱を開けよう

    2012/08/21 -

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    泡で金属をたたいて強くする

  43. 楽しい理科のはなし2012 不思議の箱を開けよう

    2012/07/17 -

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    太陽熱発電と太陽光発電－さびで作った太陽電池－ 鶴巣小学校での出前授業

  44. 奇跡の地球物語 消防車～火災と戦う先端技術～

    2012/07/15 -

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    監修および遠心ポンプ等の撮影協力

  45. 東北大と昭和大 微小な泡で歯周病治療 衝撃波発生、菌除去に効果

    2012/03/15 -

  46. 東北大学イノベーションフェア2012in東京

    2012/03/15 -

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    東北大学イノベーションフェア2012in東京に「キャビテーションテクノロジーの新展開」を出展した。

  47. 東北地域アグリビジネス創出フェア2011

    2011/12/20 -

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    東北地域アグリビジネス創出フェア2011に「流動キャビテーションによる水処理」として出展した。

  48. 出前授業（呉三津田高校）

    2011/09/28 -

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    専門分野の概要，大学での学習・研究の状況，具体的な学習内容等の説明と講演

  49. ひらめき☆ときめきサイエンス

    2011/08/12 -

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    泡で金属をたたいて強くする

  50. 楽しい理科のはなし2011 不思議の箱を開けよう

    2011/06/30 -

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    太陽熱発電と太陽光発電－さびで作った太陽電池－ 宮床小学校での出前授業

  51. ひらめき☆ときめきサイエンス

    2011/01/06 -

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    泡で金属をたたいて強くする

  52. 東北大学出前授業

    2010/12/09 -

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    作並小学校13名，2010年12月9日

  53. 東北大学イノベーションフェア2010in仙台

    2010/10/18 -

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    東北大学イノベーションフェア2010in仙台に「キャビテーションテクノロジーの新展開」を出展した。

  54. 中学生 最先端技術に 泡で金属強くする?!

    2010/07/21 -

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    「Nスタみやぎ」（東北放送）で，東北大学と仙台市教育委員会が主催した「夏休み大学探検」の「泡で金属をたたいて強くする」の実施内容と風景，インタビューが報道された。

  55. 探検！最先端 泡で金属をたたく

    2010/07/21 -

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    「スーパーJチャンネルみやぎ」（東日本放送）で，東北大学と仙台市教育委員会が主催した「夏休み大学探検」の「泡で金属をたたいて強くする」の実施内容と風景，インタビューが報道された。

  56. 夏休み大学探検2010

    2010/07/21 -

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    東北大学と仙台市教育委員会主催で，仙台市立の中学生を対象として「夏休み大学探検2010」のコースとして「泡で金属をたたいて強くする」を実施した。

  57. 一関市立川崎中学校の見学

    2010/04/15 -

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    一関市立川崎中学校からの見学者に対して，クラッシクカー（Ｔ型フォード）の展示見学および，ガソリンエンジン，ハイブリッド車，燃料電池車について，関連の実験装置の見学や，エンジンのカットモデルなどを用いて説明した。

  58. 学校スケッチ 貝森小 教授に学ぶ車の進化

    2010/03/12 -

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    東北大学機械系が主催した，貝森小学校の職場見学「東北大学機械系－自動車の過去・未来－」の様子とインタビューが朝日新聞に掲載された。

  59. 小学生が学ぶ 「自動車の過去・現在・未来」

    2010/03/09 -

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    東北大学機械系が主催した貝森小学校の職場見学「自動車の過去・未来」の実施の様子が，FNN仙台放送スーパーニュースで放映された。

  60. 東北大を訪問 小学生が最新の研究を見学

    2010/03/09 -

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    機械系が主催した貝森小学校の職場訪問「東北大学機械系－自動車の過去・未来－」の様子が，NEW リアルタイム ミヤギで放映された

  61. 職場見学「東北大学機械系 －自動車の過去・未来－」

    2010/03/09 -

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    東北大学機械系と貝森小学校が主催して，大学を一つの職場として捉え，自動車の過去と未来を具体的な例に挙げて，大学の施設や活動を体験してもらい，大学の果たす役割を小学生に実感してもらうプログラムを実施した。

  62. 科学の楽しさ知って 東北大院 親子対象に実験教室

    2010/01/10 -

  63. ひらめき☆ときめきサイエンス

    2010/01/07 -

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    泡でたたいて強くする 泡で金属をたたいて強くする

  64. 出前授業（尚絅学院高校）

    2009/10/29 -

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    ２１世紀型機械のためのナノメカニクス

  65. イノベーションフェア2009in仙台

    2009/10/14 -

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    東北大学イノベーションフェア2009in仙台に「キャビテーションピーニング－泡で叩いて金属材料を強くする－」を出展した。

  66. 出前授業（長野高校）

    2008/09/13 -

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    専門分野の概要，大学での学習・研究の状況，具体的な学習内容等の説明と講演

  67. ジェット噴流金属疲労防ぐ

    2007/12/14 -

  68. 科学技術振興機構 理科大好きボランティア

    2007/06/30 -

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    ボランティア研修会での講師

  69. 疲労強度20－50%向上

    2005/08/31 -

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    東北大が金属表面改質法 大気中にキャビテーション・ジェット発生

  70. 気中キャビテーション噴流利用

    2003/03/07 -

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    水槽不要 複雑形状に対応 東北大とムラタ製作 表面改質装置を開発

  71. １台で３噴流を実現

    2002/09/11 -

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    －キャビテーション，多様な分野で活用へ－

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Media Coverage 13

  1. さらなる高精度化・微細化進むウォータージェット技術 ポンプの高圧化による切断低コスト化 泡で金属をたたいて強くする

    日刊工業新聞

    2016/07/28

    Type: Newspaper, magazine

  2. "未来の科学者"を育成 ガソリンから燃料電池まで

    東日本放送

    2010/03/09

    Type: TV or radio program

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    「スーパーJチャンネルみやぎ」で，東北大学機械系が主催した，貝森小学校の職場見学「東北大学機械系－自動車の過去・未来－」の実施内容と風景，インタビューが報道された。

  3. 泡で金属強化!? 科学は奥が深い

    東日本放送

    2010/01/07

    Type: TV or radio program

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    「スーパーJチャンネルみやぎ」で，(独)日本学術振興会 研究成果の社会還元・普及事業 ひらめき☆ときめきサイエンス〜ようこそ大学の研究室へ〜KAKENHIとして開催した「泡でたたいて強くする」の実施内容と風景，インタビューが報道された。

  4. 冬休み最後の1日 科学への興味深めて

    東北放送

    2010/01/07

    Type: TV or radio program

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    「総力報道! THE NEWS TBC」で，(独)日本学術振興会 研究成果の社会還元・普及事業 ひらめき☆ときめきサイエンス〜ようこそ大学の研究室へ〜KAKENHIとして開催した「泡でたたいて強くする」の実施内容と風景が報道された。

  5. ばね技術研究会春季定例行事講演会

    ばね産業新聞

    2004/07/01

    Type: Newspaper, magazine

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    キャビテーション・ショットレス・ピーニング 講師祖山均氏

  6. 芽育む研究室 東北大学・祖山教授

    日刊工業新聞

    2003/07/03

    Type: Newspaper, magazine

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    気泡の衝撃力に注目 金属の表面改質などへ応用

  7. 優れものです

    日刊工業新聞

    2003/06/20

    Type: Newspaper, magazine

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    キャビテーション衝撃力計測装置

  8. キャビテーション噴流式洗浄法

    日刊工業新聞

    2002/03/07

    Type: Newspaper, magazine

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    高効率で広範囲な洗浄 表面改質への応用も実証

  9. キャビテーション噴流

    日刊工業新聞

    2001/10/12

    Type: Newspaper, magazine

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    高圧水噴射で発生に成功 東北大、水槽を不要に

  10. キャビテーション現象 正確に再現

    日刊工業新聞

    2000/02/11

    Type: Newspaper, magazine

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    ムラタ製作所実験装置を開発 材料の耐久試験効率化

  11. キャビテーションを計測

    日刊工業新聞

    2000/01/14

    Type: Newspaper, magazine

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    東北大と豊洋電子が装置

  12. 衝撃力を正確に計測

    日刊工業新聞

    1999/05/17

    Type: Newspaper, magazine

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    東北大 キャビテーションセンサー 英国大と共同開発

  13. 気泡で金属表面改質

    日刊工業新聞

    1999/04/30

    Type: Newspaper, magazine

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    東北大が開発 低コスト、短時間で硬化

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Other 28

  1. キャビテーションピーニングによる鋼ローラの疲れ寿命向上に関する研究

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    本研究は，流体機械に致命的損傷をもたらすキャビテーション気泡の崩壊時に生じる衝撃力を，逆転発想的研究により，ショットピーニングのごとく，機械部品の高強度化に活用するキャビテーションピーニングの構築を目的とする。これまでに，キャビテーションピーニングによる圧縮残留応力導入や，平面曲げ式疲労試験などを用いた種々の機械材料の疲労強度向上を実証してきたが，本研究では，トライボロジー特性向上へのキャビテーションピーニングの展開を目的として，機械部品として鋼ローラを取り上げ，キャビテーションピーニングによる鋼ローラの疲れ寿命向上に関する研究を実施する。具体的には，キャビテーションピーニングでは，キャビテーション噴流を用いて加工するので，まずノズル形状などによりキャビテーション噴流を強化した上で，噴射条件などのキャビテーションピーニングの加工条件を最適化する。なお現状ではキャビテーション衝撃力は数値解析で求められないので，実験的に加工条件を最適化するとともに，各因子によるキャビテーション噴流の加工能力を求める実験式を導出する。東北大学において好適な条件のキャビテーションピーニングで処理したローラを，岡山大学において疲れ試験を実施し，キャビテーションピーニングによる鋼ローラの疲れ寿命向上を実証するとともに，圧子押込み試験を用いた逆問題解析により加工面の降伏応力を明らかにしてキャビテーションピーニングによる鋼ローラの疲れ寿命向上の機構を解明する。またキャビテーションピーニングの実用化における信頼性を確保するために，ピーニング面の非破壊評価法を構築する。以上を総括して，キャビテーション噴流に関する流体力学的観点と塑性加工に関する材料工学的観点を融合してキャビテーションピーニングによる鋼ローラの疲れ寿命向上法を構築する。

  2. 歪制御による耐水素脆化層の創成と評価

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    本研究の目的は，金属材料の水素脆化を抑止するための表面改質の構築を目的とし，(Ⅰ)簡易型水素吸蔵量評価法の構築，(Ⅱ)ミクロ歪・マクロ歪と水素吸蔵量の相関の解明，(Ⅲ)ミクロ歪・マクロ歪と水素脆化特性の相関の解明，(Ⅳ)歪制御による耐水素脆化層の創成，なる４項目に焦点を絞り，研究を遂行する。

  3. ピーンフォーミングによる金属塑性加工における歪速度と機械的特性の解明

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    ピーンフォーミングのためのキャビテーションピーニングの最適化 塑性加工における歪速度の相違による機械的特性（降伏応力，疲労強度）の解明 衝撃力の計測と材料評価に立脚した塑性加工法の構築

  4. キャビテーションピーニングの高度化

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    一般には流体機械に致命的損傷を与える「害悪」であるキャビテーション気泡崩壊時に生じる衝撃力を，逆転発想的に，機械部品の強度を向上させる表面改質に有効利用するキャビテーションピーニングを取り上げ，本研究ではキャビテーションピーニングの実用化を目途として，キャビテーションピーニングの高度化を図る。本研究における「キャビテーションピーニングの高度化」とは，キャビテーションの発生領域を制御して，「キャビテーションピーニングの加工能力向上」と，「キャビテーションピーニングの加工領域の集中化」を意味する。具体的には，キャビテーションピーニングに用いるキャビテーション噴流の加工能力について単位時間当たり単位面積当たりの加工能力の２倍以上の向上，キャビテーションピーニングの加工槽圧力が高いキャビテーション数0.02以上の条件において加工能力が２倍以上のノズル形状の設計指針の明示，キャビテーションピーニングによるショットピーニングと同等以上の疲労強度向上の実証，マイクロビッカース硬さを用いたキャビテーションピーニング層の簡易評価手法の構築，キャビテーションピーニングによる特殊鋼の水素脆化抑止の実証を行う。

  5. 口腔洗浄装置に応用する流動キャビテーション・ベンチュリ管の開発

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    本発明は流動場によりキャビテーションを発生させており、バイオフィルムの洗浄にはこの流動キャビテーションの崩壊衝撃作用を活用している。効率よく洗浄するには、流動キャビテーションを発生させるノズル形状を最適化する必要がある。キャビテーション流れは、相変化を伴う高レイノルズ数領域の流れなので、数値シミュレーションによりノズル形状を最適化することは不可能である。従って、ノズルを試作して東北大学祖山教授らが開発したキャビテーションインパクトカウンタでキャビテーション衝撃エネルギーを評価して、ノズルを最適化する必要がある。

  6. 胃粘液の洗浄に関する研究

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    胃粘液の洗浄に関する研究

  7. 口腔内の洗浄に関する研究

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    流動キャビテーションを用いた口腔内の洗浄に関する研究

  8. Research on cavitation peening and laser peening

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    キャビテーションピーニングおよびレーザピーニングの相違に関する金属材料学的研究

  9. 流動キャビテーションによるラジカルの制御

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    キャビテーション気泡の崩壊時に生じる物理的作用である衝撃力を，金属材料への圧縮残留応力導入に活用して原子炉の応力腐食割れ抑止法として実用化してきた研究代表者の流動キャビテーションに関する知見を基盤とし，本研究では，流動キャビテーションによる化学的作用を産業的に活用する方法を構築する。従来，超音波キャビテーションを対象とした音響化学という分野があるが，本研究は，超音波キャビテーションよりも桁違いに強力な流動キャビテーションを用い，気泡崩壊時に生じるラジカルに着目して研究を遂行し，キャビテーションによる化学的作用の実用化を図る。具体的には，流動キャビテーションを用いたキャビテーション・リアクターを試作して，気泡崩壊時に生じる微弱発光の分光分析や電子スピン共鳴法によりラジカルを評価して，流動キャビテーションによるラジカルの制御法を構築する。

  10. キャビテーションピーニング

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    キャビテーションピーニングによる摩擦磨耗特性向上

  11. 養殖へのキャビテーションテクノロジーの新展開

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    キャビテーションは，一般には流体機械に害悪を与える現象であるが，本研究は，逆転発想的研究により，キャビテーションをナマコなどの養殖に害となるプランクトンの殺滅などに活用するなど，代表研究者の有するキャビテーションテクノロジーの養殖への新展開を図る研究である。本研究では，キャビテーションを強力化して制御し，養殖への実用化のための最適条件を明らかにする。

  12. 表面処理した表面層並びに溶接部近傍の残留応力評価の研究

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    本研究の目的は，原子力プラントにおける応力腐食割れの予防・保全を目途とした溶接部の残留応力の評価である。本研究では，特に，溶接後に用いられる表面処理による表面層の残留応力と，溶接部近傍の残留応力に着目して研究を遂行する。

  13. 次世代キャビテーション・ピーニングの補修技術への展開

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    溶接補修部へ適用できるキャビテーション・ピーニング法の構築

  14. 次世代キャビテーションピーニング装置

  15. 次世代キャビテーション・ピーニングの研究開発

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    キャビテーション気泡の崩壊衝撃力を強力化してピーニングに有効利用する表面改質装置の開発

  16. 次世代キャビテーション・ピーニング用のノズルの開発

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    代表研究者は，流体機械に致命的損傷を与えるキャビテーション気泡の崩壊時の衝撃力を，逆転的発想により，ショット・ピーニングのごとく，金属材料の強度を向上させる表面改質に利活用するキャビテーション・ピーニングを開発してきている。本ピーニングは，ショット・ピーニングと異なり，ショットを用いないので，固体接触を生じないために加工面の粗さを増大することなく加工でき，疲労強度を従来のショット・ピーニングよりも向上できる利点がある。本試験研究では，これまでのキャビテーション・ピーニングの10倍以上の加工能力を有する次世代キャビテーション・ピーニング用ノズルを開発する。

  17. キャビテーション・ピーニング用多孔ノズルの開発

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    キャビテーション・ピーニング用多孔ノズルの開発

  18. キャビテーション・ショットレス・ピーニング技術の適用研究

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    キャビテーション・ショットレス・ピーニング技術の適用研究

  19. キャビテーション・ショットレス・ピーニング(CSP)の開発

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    キャビテーション・ショットレス・ピーニングの実用化研究

  20. キャビテーション・ショットレス・ピーニングの研究開発

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    キャビテーション・ショットレス・ピーニングの研究開発

  21. キャビテーション噴流可視化装置

  22. キャビテーション・ショットレス・ピーニング装置

  23. キャビテーション噴流式壊食試験装置

  24. ハイブリッド表面改質へのキャビテーション噴流の有効利用に関する研究

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    ハイブリッド表面改質へのキャビテーション噴流の有効利用に関する研究

  25. キャビテーション噴流式ハイブリッド表面改質法の開発

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    キャビテーション噴流式ハイブリッド表面改質法の開発

  26. A study on a Cavitating Jet for Hybrid Surface Modification

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    ハイブリッド表面改質へのキャビテーション噴流の有効利用に関する研究

  27. キャビテーション・インパクト・カウンタ

  28. 高速水中水噴流による長尺細管の内表面改質特性に関する研究

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    高速水中水噴流による長尺細管の内表面改質特性に関する研究

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