无网格法模拟复合型疲劳裂纹的扩展  

SIMULATION OF MIXED MODE FATIGUE CRACK GROWTH BY EFG METHOD

作　　者：袁振[1] 李子然[1] 吴长春[1] 

机构地区：[1]中国科技大学力学与机械工程系,安徽合肥230026

出　　处：《工程力学》2002年第1期25-28,共4页Engineering Mechanics

基　　金：国家自然科学基金资助项目(19772051)

摘　　要：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。The element-free Galerkin method for predicting fatigue crack propagation path and structure lifetime under mixed mode loading is presented. 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 KI and KII are computed. The crack deflection angle Φ0 is determined by the criterion of maximum stress in tangential direction. An assumed crack increment Δa, for each computing cycle delivers an estimation for the number of load cycles ΔN, 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.

关 键 词：无网格GALERKIN法 疲劳裂纹 裂纹扩展 复合变形 疲劳寿命 断裂力学 工程设计 

分 类 号：O346[理学—固体力学]