基于连续介质损伤力学理论并结合修正循环强度系数法,研究非比例加载对材料高周疲劳寿命的影响,建立一种多轴应力当量折算高周疲劳损伤强化模型。同时根据常规微塑性应变高周疲劳损伤演化模型给出的S-N曲线方程以及修正循环强度系数法基本原理对所建模型的材质参数识别方法进行阐述。以航空工业常用的金属材料铝合金LY12CZ和30CrMnSiA钢为计算实例,得到两种材料的模型参数。将已建的损伤演化模型嵌入到ABAQUS的UMAT子程序中,实现了对受损试件的损伤追踪以及寿命预测。两种材料计算结果表明,新建模型的预测效果均在3倍误差以内,与试验吻合较好。此外,还对比分析现有的其他多轴寿命预测模型的预测效果,结果表明,新建模型更适合于多轴高周疲劳寿命预测。
Based on continuum damage mechanics theory and corrected cycle intensity factor method, the effect of non-proportional loading on high-cycle fatigue life is investigated. Consequently, a hardening model with multiaxial stress equivalent conversion and high cycle fatigue damage is established. Simultaneously, in the base of S-N curve equation based on the conventional micro-plastic strain high-cycle fatigue damage evolution model and the basic principles of corrected cycle intensity factor method, a material parameter identification method of model is described. Take the metal material of aluminum alloy LY12CZ and 30CrMnSiA steel commonly used in aeronautic industry as examples, model parameters of two kinds of material are obtained. Embed the established damage evolution model into the UMAT subroutine in ABAQUS, and realize the damage tracking and life prediction for specimens. The calculation results of two materials show that the predictive effect of new models are both in the error of less than 3 times, and in good agreement with experiment. In addition, compare and analyze the predictive effect of other existing prediction models, and the results indicate that the new developed model is more suitable for life prediction of multiaxial high cycle fatigue.