考虑冲击缺陷的钛合金板的疲劳寿命预估

基于连续损伤力学理论，研究了含冲击凹坑缺陷的Ti-1023钛合金板的疲劳损伤问题。通过分析冲击损伤与疲劳损伤的共同作用以及应力场与损伤场的耦合作用，对含冲击凹坑的钛合金板的疲劳寿命进行了预估。首先，基于连续介质运动学理论，采用非线性动力学有限元分析软件进行冲击损伤的模拟，得到冲击凹坑处的残余应力场与塑性应变场。其次，根据塑性损伤方程，计算冲击凹坑局部的初始损伤场，并将其作为后续疲劳计算的初始条件。然后，采用Chaudonneret的多轴疲劳损伤力学模型建立损伤力学-有限元数值解法，以进行损伤演化过程的数值计算。最后，综合考虑残余应力场、塑性初始损伤和疲劳损伤的共同作用，对含冲击凹坑的钛合金板进行了疲劳寿命预估，并进行了相应的疲劳验证试验。结果表明，预估结果与试验结果相一致。所做研究为工程中采用损伤力学方法来预估含冲击损伤的结构的疲劳寿命提供了一种可行的方法。

Fatigue life prediction for titanium plate considering impact defect

Based on the theory of continuum damage mechanics, fatigue life prediction for Ti-1023 titanium plate with impact pit is studied. By analyzing the combined effect of impact damage and fatigue damage, considering the coupling effect of stress field and damage field, the fatigue life of titanium plate with impact pit is predicted. Firstly, on the basis of the continuum kinematics theory, the nonlinear dynamic finite element analysis software is used to simulate the process of impact damage, and the residual stress field and plastic strain field around impact pit are also obtained. Secondly, the initial damage field is calculated according to the plastic damage model, which will be input as the initial conditions of the subsequent fatigue calculation. Then, the multiaxial fatigue damage model of Chaudonneret is adopted and the damage mechanics-finite element numerical method is proposed to conduct the damage evolution calculation. Finally, this method is used to predict the fatigue life of titanium plate with impact pit and the corresponding fatigue tests are conducted for validation. The results show that the prediction lives are in accordance with test data. The research provides a feasible method for fatigue life prediction of metal component with impacted damage in engineering practice.