关键词: 参数识别, 当量折算, 多轴高周疲劳, 非比例加载, 损伤力学

Abstract: 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.

Key words: damage mechanics, equivalent conversion, multiaxial high-cycle fatigue, non-proportional loading, parameters identification