考虑残余应力释放的疲劳寿命预测方法研究

Study on fatigue life prediction method consideving the residual stress release

基于断裂力学理论,考虑残余应力及加载过程中的应力释放对接头疲劳性能的影响,探索不等厚对接接头疲劳寿命的预测方法。采用三维有限元理论研究不等厚板接头的残余应力分布规律,并通过残余应力释放模型和Forman公式计算加载过程各瞬态的有效应力强度因子和有效应力强度因子比,得到不等厚对接接头的疲劳寿命,将预测值与疲劳试验结果进行对比。结果表明:不等厚对接接头疲劳寿命的预测与试验结果是一致的,该模型可用于不等厚对接接头疲劳寿命的预测。

The effect of residual stress and stress release during loading on the fatigue performance of butt joint with unequal thickness was studied,a prediction method for fatigue life was established using fracture mechanics theory.The residual stress distribution law of unequal thickness butt joint was investigated using the three-dimensional finite element theory,and the effective stress intensity factor and its ratio were calculated by the residual stress release model and the Forman formula.And the fatigue life of unequal thickness butt joint was calculated,the predicted value was then compared with the fatigue test result.The results show that the fatigue life predicted by the model is consistent with the experimental result.The model can be used to predict the fatigue life of unequal thickness butt joints.