| Project/Area Number |
61460094
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械工作
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
FUKUNAGA Hideharu Faculty of Engineering, Hiroshima University, Professor, 工学部, 教授 (90034347)
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| Co-Investigator(Kenkyū-buntansha) |
GODA Koichi Faculty of Engineering, Hiroshima University, Assistant, 工学部, 助手 (10153743)
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| Project Period (FY) |
1986 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1988: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1987: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1986: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | FRM / Strength / Reliability / Weibull Distribution / Ceramic Fiber / Shear-Lag Theory / Finite Difference Method / シミュレーション / 引張強さ / 強度評価 / 寸法効果 / 弾塑性有限要素法 / ミアラグ理論 / 信頼性解析 / モンテカルロシミュレーション / 繊維強化金属 / SiC繊維 / ボロン繊維 / アコースティックエミッション |
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| Research Abstract |
The research on reliability of Frm was carried out as described below, and it led to the useful results. 1) Tensile tests on several kinds of reinforcing ceramic fibers and its statistical analysis. 2) Tensile tests and their statistical analysis on boron fiber reinforced aluminum composites which are prepared in the study. 3) Computer simulation for tensile fracture of the composites.
The results obtained are as follows; 1) The strength distribution of fibers can be expressed by multi-modal Weibull distribution. This distribution function gives appropriately the transition of the average strength and the coefficient of variation with the contact time of the fiber with liquid aluminium. Three kinds of defects, namely, inner, surface and reaction product, which are the initiation point of fracture, were observed by SEM. Finally, the defect due to the reaction product controlls the strength distribution when the reaction between fiber and matrix becomes very intenes. 2) Reliability of Frm
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is largely dependent of the statistical characteristics of the fiber strength and the fracture process of the composites. In the case of the non-cumulative fracture the strength distribution obeys the minimum value distribution of fiber strength, but the cumulative fracture process enhances the reliability of strength. 3) The results mentioned above were supported by monte-calro simulation technique using shear-lag theory. However, this theory cannot treat the normal stress of matrix along the axial direction, so that a problem remains for analyzing strictly the stress destribution. On the other hand, the cumulative distribution curve of strength was predicted by recursion analysis technique, which is a method of evaluating probabilistically the strength of unidirectional composites using the Weibull parameters of fiber obtained from tensile-testing. The results showed that the curve matched well with the Weibull plots of experimental data. 4) Furthermore, the present work suggests a new testing method to estimate the Weibull parameters on the condition that the fibers are embedded in matrix. Less
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