![]() Thus, the superposition of residual stress and working stress produces a complex stress state and high stress gradient. The distribution of residual stress usually increases first and then decreases along the depth direction. The residual stress introduced by shot peening can suppress the initiation of fatigue cracks, and the fatigue life of components is enhanced. In the field of engineering machinery, it is possible to effectively improve the fatigue life of components by shot peening. Therefore, the working stress produced by fretting has a great gradient along the depth direction, which is an important difference between fretting fatigue and plain fatigue. For fretting fatigue, the cyclic contact stresses acting on the component are composed of contact pressure and contact shear stress. Under cyclic contact stresses, fretting facilitates the premature initiation of fatigue cracks due to stress concentration, which leads to a shorter fatigue life of the components. ![]() However, the opposite phenomenon appears when the fatigue loading is large enough.įretting caused by cyclic contact stresses can occur at any place when there is a small relative motion between two components. Furthermore, under smaller fatigue loading, the crack initiation life of specimens with high shot peening intensity is longer than that of specimens with low shot peening intensity. The remaining residual stress decreases with the increase of fatigue loading, and the effect of shot peening on the improvement of crack initiation life is more obvious under smaller fatigue loading. The results show that the remaining residual stress after relaxation strongly affects crack initiation life. Considering that the fretting contact region has a high stress gradient along the depth direction, the process volume approach is adopted to calculate the SWT parameters. The crack initiation life is predicted by the critical plane Smith–Watson–Topper (SWT) model. The residual stress relaxation and the contact stress evolution are both considered. ![]() This study analyzes the effects of shot peening on the crack initiation behavior under fretting loading by using a numerical method. ![]()
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