| Project/Area Number |
17K14714
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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 |
Structural engineering/Earthquake engineering/Maintenance management engineering
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| Research Institution | Yokohama National University (2019)
Tokyo Institute of Technology (2017-2018) |
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Principal Investigator |
Tamura Hiroshi 横浜国立大学, 大学院都市イノベーション研究院, 准教授 (10636434)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
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| Keywords | 鋼部材 / 表面亀裂 / 繰返し弾塑性変形 / 分岐問題 / 延性亀裂 / 極低サイクル疲労亀裂 / 鋼構造物 / 耐震設計 / 加工硬化層 / 構造工学・地震工学 / 耐震 |
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| Outline of Final Research Achievements |
The purpose of this study was formulation of surface crack initiation criteria for steels subjected to cyclic plastic strain history, which is necessary for the evaluation of resistance to brittle fracture of steel structures during earthquakes. The research could be divided into three phases: 1) validation of the hypothesis regarding the mechanism of surface crack initiation, 2) development of numerical simulation method, and 3) formulation of surface crack initiation criteria. Regarding 1), it was mostly achieved. In 2), the expression of spatial periodicity could be qualitatively reproduced by developed simulation. Regarding 3), the examination is insufficient, and it is at the stage where it is necessary to improve the versatility of the simulation.
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| Academic Significance and Societal Importance of the Research Achievements |
表面亀裂形成過程について申請段階では，繰返し変形の中の圧縮過程において微視的に空間的周期性を有するしわ状の凹凸が表面に形成され表面亀裂の発生過程に深く関わっているという見解をもっていたが，これは仮説の域を出ていなかった．また，凹凸の形成は材料の微視的構造よりもむしろ分岐現象として材料を連続体とみなして説明可能であるとの見通しについても裏付けが不十分であった．本研究によって，これらの見解，見通しについての実証を大きく前進させることができた．
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