鈍化裂縫前端彈塑性變形之探討

• Main Authors: Wang, June-Wen, 王俊文
• Other Authors: Chiang, Chun-Ron
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/23489035056556865727

碩士 === 國立清華大學 === 動力機械工程學系 === 94 === This thesis is analyzed an elastic-plastic material with a crack by using Finite Element Method simulation, and suppose there is a blunt crack with a curvature radius which is equal to 0.5mm. For the model I loading and the small scale deformation, the stress intensity factor KI and strain hardening of material influence caused toward stress strain and plastic zone distribution of the crack tip. The material property relies primarily on bilinear-plasticity mechanics model and kinematics hardening law. From the result of this work, because of the blunted crack tip (ρ=0.5mm), the position of the maximum value of stress of y direction is equal to 1.649 mm measured from crack tip, when the original strain hardening law of material is equal to 0.003585 and the stress Intensity Factor KI is equal to 2300 MPa . The strain hardening rate is greater than 0.02 and will reach the maximum in the stress of y direction of crack tip. In the range of plastic zone, the strain hardening rate of material strongly influences the distribution of stress and strain.