| Project/Area Number |
18560073
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | The University of Electro-Communications |
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Principal Investigator |
OCHI Yasuo The University of Electro-Communications, Faculty of Electro-Communications, Professor (70017416)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMURA Takashi The University of Electro-Communications, Faculty of Electro-Communications, Associate Professor (00251710)
MASAKI Kiyotaka Okinawa National College of Technology, 機械システム工学科, Associate Professor (30323885)
KAKIUCHI Toshifumi The university of Electro-Communications, Graduate School of Electro-Communications, Research Associate (20452039)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,770,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥270,000)
Fiscal Year 2007: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2006: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Laser peening treatment / Fatigue strength reliability / Fatgiue crack propagation control / Machine and structural materials / Micro computed tomography (μCT) / Crack profile obserbation / Compressive residual stress / Strain hardeing layer / レーザビーニング処理 / 疲労き製造展抑制 / 機械構造部材 / 疲労強度信頼性 / 疲労き裂進展 / 応力拡大係数 / ステンレス鋼 / アルミニウム合金 |
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| Research Abstract |
It is useful for the reducing of weight, energy, materials and the high efficiency to improve the fatigue strength reliability of machines and structures by giving high functional property. In the present research, the laser peening (LP) treatment is performed on machines and structural materials, and it is the porpose of the research to improve the fatigue strength reliability in the materials and to make clear the mechanism of the improvement The laser treatment of low energy YAG laser without protective coating is wsasused in water The materials used in the research a were austenitic stainless steels for nuclear plant structures, cast aluminum alloy for automobile parts and high strength tool steels.
The main conclusions obtained in the research are as followings
1. In all of the materials used in the research, it is confirmed to improve the fatigue strength by the LP treatment. And it is clear that the improvement effects were induced from compressive residual stress and the strain hardening in the surface layer of materials by the LP treatment.
2. The restrained effects for fatigue crack propagation process were confirmed for the pre-cracked materials by the LP treatment And, the effects were induced from the compressive residual stress and the crack closure effect by plastic deformation near crack tip by the LP treatment.
3.By the micro computed tomographic (μ CT) imaging technology with syncroton radiation equipment, surface fatigue cracks were successfully visualized non-destructively and three-dimensionally.
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