无网格法模拟复合型疲劳裂纹的扩展

本文提出了用无网格Galerkin法模拟构件在复合变形作用下疲劳裂纹扩展路径并预估其疲劳寿命的方法。该法能够自然模拟疲劳裂纹的扩展,不需要网格重构,避免了裂纹扩展过程中的精度受损。应用无网格数值结果计算了J积分和应力强度因子IK和IIK;按照最大周向应力理论获得了裂纹扩展偏斜角。基于最小应变能密度因子理论,确定了裂纹扩展量aD,并能获得疲劳载荷的循环周数ND。文末对数值模拟结果和实验拟合结果进行了对照。

SIMULATION OF MIXED MODE FATIGUE CRACK GROWTH BY EFG METHOD

The element-free Galerkin method for predicting fatigue crack propagation path and structure lifetime under mixed mode loading is presented in this paper. This method is used in order to allow for crack growth without remeshing and the degradation in accuracy with crack propagation in simulation process is overcome successfully. Using the results of a EFG method analysis, the J-integral and stress intensity factors IKand IIK are computed. The crack deflection angle 0F is determined by the criterion of maximum stress in tangential direction. An assumed crack incrementaD, for each computing cycle delivers an estimation for the number of load cycles, ND, using the strain energy density factor theory. Numerical results for a CGS-04-specimen made of Ti-6Al-4V are presented and compared with experimental data.