| Project/Area Number |
07455281
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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 |
Structural/Functional materials
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| Research Institution | TOYOHASHI UNIVERSITY OF TECHNOLOGY |
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Principal Investigator |
KOBAYASHI Toshiro Toyohashi University of Technology, Department of Engineering, Professor, 工学部, 教授 (90023324)
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| Co-Investigator(Kenkyū-buntansha) |
TODA Hiroyuki Toyohashi University of Technology, Department of Engineering, Lecture, 工学部, 講師 (70293751)
山本 勇 豊橋技術科学大学, 工学部, 助手 (50230537)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥6,100,000 (Direct Cost: ¥6,100,000)
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| Keywords | MMC / FEM / PFZ / simulation / crack propagation / microcracks / crack-tip singularity / 金属基複合材料 / き裂伝播 / FEM解析 / 非平衡偏析 / 強度 / 破壊じん性 / SiCウィスカ- / 復元再時効処理 / 偏析 / 時効析出 |
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| Research Abstract |
Effects of locally-inhomogeneous microstructures, such as PFZ layrs around reinforcements, coarse interfacial equilibrium precipitates, solute atom segregation, on deformation and fracture characteristics of the MMCs are analyzed by means of the elastic-plastic finite element analysis.
Due to the ductile nature of the PFZ layrs, concentrated plastic flow within the PFZ layrs promotes increase of effective plastic strain in the whole matrix, thereby reducing stregth of the MMCs. On the other hand, the interfacial precipitates effectively retard the concentrated plastic flow within the PFZ layrs and consequently they suppress reduction of the strength due to the formation of the PFZ.The initiation rate of the void is remarkably affected by the morphologies and density of the precipitates.
Taking above-mentioned microstructural features into account, we constructed a simulation program which simulates crack propagation through the discontinuously-reinforced. Micro-cracking, crack deflection, interaction between the main crack and the microcracks, and transition of stationary to non-stationary crack-tip singularities are taken into consideration in the simulation. Effects of the various microstructural parameters on the crack propagation resistance are evaluated. The most interesting information of this study is that the properly inhomogeneous distribution of the reinforcement improves the crack propagation resistance. We also evaluated static strength of such composites having reinforcement segregation by means of numerical simulation. The optimum microstructural configuration was proposed by the simulation.
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