Fatigue life calculation for a specimen with an impact pit considering impact damage, residual stress relaxation and elastic-plastic fatigue damage

In this study, a continuum damage mechanics based method is proposed to calculate the fatigue life of a specimen with an impact pit. The impact process is simulated by a quasi-static analysis. The residual stress and the impact damage are calculated. Then, the elastic-plastic fatigue damage of the material is considered as the specimen experiences cyclic loading. The residual stress relaxation is investigated via a coupled analysis of the residual stress and elastic-plastic damage evolution. The calculated results agree well with the experimental results. The effects of the impact depth and radius that the impact object has on the fatigue failure are also discussed.