B201 球状黒鉛鋳鉄と鍛鋼の非線形破壊力学による延性破壊評価 : J 積分設計曲線の提案

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Based on the ductile fracture tests resolts of Ductile Cast Iron and Forged Steel using large-scaled flat test specimens with crack, the evaluation method of initiation of ductile fracture of a cask body with crack by J-integral were developed, and several formula was proposed. And a concrete application method of obtained formula was proposed in case of Cask drop accident. Following results were obtained. 1) By using bose Non-dimensional J-integral Φ(=J/Eεy ^2a or J/2πEεy ^2a) and Non-dimensionalizd strain (ε/εy), the differance caused by materials cames into small and J-ε overall curves become together into one curve. 2) Obtained J-integral design curves : Φ=(f^2/2)(ε/εy)^2 for ε/εy<1,Φ=f^2(ε/εy^<-0.5>) for ε/εy≧1 ε overall/εgross=8.1537(y/a)^<-0.7347> Φ : Non-dimensional J-integral (Φ=J/2πEεy ^2a), f : Shape Factor, εy : YieldStrain, ε : Strain ε overall : Overall Strain, ε gross : Gross Strain, y : GageLength×1/2,a : Equivalent Crack Length×1/2
2000-10-30