【摘要】 文章提出了一种基于裂纹尖端弹塑性应力应变关系的预测变幅载荷下疲劳裂纹扩展的方法。该方法通过对裂纹前端过程区单元的弹塑性应力的循环叠加,得到裂纹扩展过程中的应力、应变关系,兼顾了残余应力对裂纹扩展的作用。基于累计损伤理论,同时利用SWT应力应变和寿命的关系,对单元损伤量的循环叠加计算,根据损伤量判断单元破坏。该方法能够清楚地反映过载时裂纹扩展的迟滞效应和低载对裂纹扩展的加速影响,并对变幅载荷下疲劳裂纹的扩展进行良好的评估。更多还原

【Abstract】 A method of predicting fatigue crack propagation is presented.This method is based on the elasto-plastic stress and strain analysis of process zone ahead of crack-tip,and the theoretical basis for calculating the fatigue crack length is the accumulation damage theory.Residual stress is included by cycle accumulating of stress in the elements located in the process zone.Using SWT equation,the fatigue damage is obtained by cyclic damage accumulation of crack-tip.This method can represent the retardation of crack growth under overloading and the acceleration enduring underloading clearly,and gives a satisfactory prediction for fatigue crack growth especially for variable amplitude loading cases.更多还原