| Project/Area Number |
13450407
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
海洋工学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
YOSHINARI Hitoshi The University of Tokyo, Fuculty of Engineering, Assistant Professor, 大学院・工学系研究科, 助教授 (20167737)
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| Co-Investigator(Kenkyū-buntansha) |
KANEDA Shigehiro The University of Tokyo, Fuculty of Engineering, Research Associate, 大学院・工学系研究科, 助手 (90010892)
高橋 淳 東京大学, 大学院・工学系研究科, 助教授 (10222085)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥11,100,000 (Direct Cost: ¥11,100,000)
Fiscal Year 2002: ¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 2001: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | 2-D numerical simulation / cleavage crack / grain size / crack path / Charpy test / fractured surface / crystal texture / pop-in phenomena / 亀裂伝搬経路 / ポップイン挙動 / へい開破壊 / 結晶粒 / シャルピー試験片 / 伝播シミュレーション |
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| Research Abstract |
We studied on mechanisms of cleavage crack propagation in steels from mesoscopic view by 2-D numerical simulations and investigated the effects of some factors on crack path and morphology of the fractured surface. Assumptions used in simulations are that a crack propagates through cleavage plane of each grains and fracture initiation is dominated by maximum tensile stress of that plane. Stress field solutions of crack by FEM and the kink-crack analysis of Cottrel & Rice were used in simulation. For small scale yielding crack in the multi-axial stress mode, the solutions by Shih was used, too. The results simulated were compared with Charpy test and other fracture tests. As for the crystal grain diameter, fracture surface for random size of grains was rougher than constant one, and elastic-plastic cracks than elastic. Irregularity of fractured surface of cristal textures was increased as compared to the case of random distributed grains. These correspond with the experimental results from the viewpoint of tendency. Although the pop-in phenomena have been considered to take place by non-homogenious toughness of materials, it was shown that a small ckack could stop by only crack kinks. As far as crack is small, the above things can be said. But, when initial crack size is large, crack path becomes almost constant despite of grain sizes and cristal textures.
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