Changing mechanisms of surface topography and the fatigue damage assessment in cyclically loaded metal materials
| Project/Area Number |
17K14552
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Hokkaido University |
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Principal Investigator |
FUJIMURA Nao 北海道大学, 工学研究院, 助教 (40732988)
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| Project Period (FY) |
2017-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2017: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
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| Keywords | 表面性状 / 疲労損傷評価 / ステンレス鋼 / 機械材料・材料力学 / 疲労 / 表面粗さ |
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| Outline of Final Research Achievements |
To propose the evaluation method for a seismic-loaded damage based on the changes in surface topography of material due to cyclic plastic deformation, this study investigated the changing mechanisms of the surface topography of the low-cycle fatigued specimen using a laser microscope and discuss the relationship between the topography and surface texture parameters. The surface topographies were analyzed by frequency analysis to separate the surface relief due to persistent slip bands from that due to crystal grain deformation. The heights caused by them were measured respectively, and compared with the changes in surface profile parameters during the cyclic loading. A comparison between the height of surface relief caused by each mechanism and the surface texture parameters showed that they strongly correlated with each other. This result showed that measuring the surface texture parameters is a useful method to evaluate the degree of damage based on the fatigue process.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では，地震のような過大な荷重を受けた材料の疲労損傷を非破壊で検出するために「表面性状」に着目した．この計測にレーザー顕微鏡を用いたことでミクロンオーダーの微細形状を測定することができ，繰返し塑性変形によって材料の表面に形成された微細な凹凸の発達機構と表面性状パラメータとの関係を定量的に示すことができた．被災した重要施設では目視点検や硬さ測定で健全性評価を行っているが，目に見えない小さなひずみを検出する手法は確立されていない．表面性状を測定することは，このような損傷を材料の疲労過程に基づいて評価できる有用な手段であると考えられ，設備の信頼性の向上ならびに安全性の保証につながると期待できる．
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Report
(3 results)
Research Products
(4 results)
