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光滑试件疲劳时因表面处于平面应力状态其屈服强度比整体材料低，首先发生滑移，因而造成疲劳损伤，达到一定疲劳周次后积累的损伤导致断裂，因而表层屈服强度和疲劳极限之间存在对应关系。缺口试件引入残余压应力，由于应力集中效应，缺口根部的残余应力集中系数可能高于理论应力集中系数，因而其疲劳强度将超过最高的光滑试件疲劳强度。考虑残余应力对裂纹扩展的作用时应计及其衰减的作用。
When the smooth specimen is fatigue, its yield strength is lower than that of the whole material due to the surface being in the plane stress state, and the slip occurs first, resulting in fatigue damage. After a certain period of fatigue, the accumulated damage leads to fracture and thus the yield stress between the surface and the fatigue limit There is a correspondence. Because of the stress concentration effect, the residual stress concentration coefficient at the notch root may be higher than the theoretical stress concentration factor, so the fatigue strength will exceed the fatigue strength of the highest smooth specimen. Consideration of the effect of residual stresses on crack propagation should be accounted for.