基于A-F类循环塑性理论的多轴局部应力应变法

MULTIAXIAL LOCAL STRESS-STRAIN APPROACH BASED ON A-F TYPE CYCLIC PLASTICITY THEORY

提出预测缺口构件疲劳寿命的多轴局部应力应变法。采用Armstrong-Frederick(A-F)类循环塑性理论,描述具有非Masing特性的16MnR材料的循环塑性行为。结合A-F类循环塑性模型和增量式Neuber法,分析比例和非比例加载下缺口根部处的多轴应力应变状态。将局部应力应变应用于基于临界面的多轴疲劳损伤模型,对缺口构件进行疲劳损伤分析和疲劳寿命预测。分析结果表明,基于A-F类循环塑性理论的多轴局部应力应变法,能很好地描述缺口根部处的多轴应力应变状态,疲劳寿命的预测结果与试验数据基本吻合。

A multiaxial local stress-strain method was proposed to predict the fatigue life of notched components.The Armstrong-Frederick（A-F） type cyclic plasticity theory was adopted to describe the cyclic plasticity behavior.This newly developed cyclic plasticity theory is able to characterize the non-Masing behavior of 16MnR steel.The multiaxial stress-strain state at the notch root of notched components subjected to proportional and non-proportional loading was predicted by combining the A-F cyclic plasticity model and the incremental Neuber＇s rule.On the basis of the multiaxial local stress-strain state and a critical plane based multiaxial fatigue damage criterion,the fatigue damage of the notched components was analyzed and then the fatigue life was predicted.The numerical results show that the proposed multiaxial local stress-strain method can describe the multiaxial stress state at the notch root very well,and the predicted fatigue lives correlate well with the experimental data.