For fretting fatigue, micro-slipping often causes initial micro-cracks in the contact surfaces, which gradually propagate and eventually result in fracture failure. However, it is difficult to directly observe and measure the crack initiation and propagation processes of single-lap bolted joints due to the obstacle of testing technique. Therefore, this article presents an elastic analysis–based method, in which the total fretting fatigue lifetime is divided into initiation life predicted by continuum damage mechanics and propagation life calculated by SEAM Tool in combination with Paris’s law. Since the initiation life model implicitly reflects the result of damage process, one can directly calculate the initiation life based on the elastic stress analysis. The predicted fretting fatigue life, initial crack location, and propagation path are in reasonable agreement with the fretting fatigue test and scanning electron microscope observation results. In addition, it is found that among the main factors affecting fretting fatigue of steel single-lap bolted joints, the initial life is affected by cyclic stress, friction coefficient, and tightening torque, and the propagation path is mainly influenced by tightening torque.

中文翻译：

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使用连续损伤力学和 SEAM 工具数值估算螺栓接头的微动疲劳寿命

对于微动疲劳，微滑移往往会在接触面产生初始微裂纹，并逐渐扩展并最终导致断裂失效。然而，由于测试技术的障碍，很难直接观察和测量单搭接螺栓接头的裂纹萌生和扩展过程。因此，本文提出了一种基于弹性分析的方法，将微动疲劳总寿命分为连续介质损伤力学预测的起始寿命和 SEAM Tool 结合巴黎定律计算的扩展寿命。由于起爆寿命模型隐含地反映了损伤过程的结果，因此可以根据弹性应力分析直接计算起爆寿命。预测的微动疲劳寿命、初始裂纹位置、和传播路径与微动疲劳试验和扫描电镜观察结果吻合较好。此外还发现，在影响钢制单搭接螺栓接头微动疲劳的主要因素中，初始寿命受循环应力、摩擦系数和拧紧扭矩的影响，传播路径主要受拧紧扭矩的影响。