2A12铝合金微动疲劳全寿命预测方法研究

目的对于2A12铝合金,提出基于成核寿命和扩展寿命的微动疲劳全寿命预测方法。方法基于损伤力学法计算裂纹成核寿命,利用扩展有限元计算裂纹尖端应力强度因子,应用断裂力学计算裂纹扩展寿命,并对预测者和试验值进行比较。结果损伤力学法能考虑接触面应力三维度的作用来反映多轴状态作用,能有效模拟微动疲劳多轴行为。基于损伤力学法的微动疲劳全寿命预测模型能有效预测微动疲劳全寿命。由于微动作用,裂纹成核非常早,扩展寿命从试件的近表面开始,占全寿命的主要部分。结论考虑成核寿命和扩展寿命的微动疲劳全寿命分析是完善的,预测值与试验值比较吻合。

Research of Fretting Fatigue Holistic Life Prediction Method for 2 A12 Aluminum Alloy

Objective The holistic life prediction approach for fretting fatigue was proposed for 2A12 aluminum alloy based on initiation life and propagation life. Methods The initiation life was calculated using continuum damage mechanics approach, and the propagation life was calculated using fracture mechanics approach with SIF obtained from XFEM. The prediction life was compared with the test life. Results The results indicated that the damage mechanics approach could consider the effect of the stress triaxiality which reflected the multiaxial stress state property. The model could effectively predict the fretting fatigue holistic life. The crack initiated quickly because of fretting, and the crack propagation began from the near surface, and the propagation life accounted for the main part of holistic life. Conclusion The holistic life prediction model considering initiation life and propagation life was perfect, and the prediction life coincided well with the test life.