High cycle fatigue behavior prediction of shot-peened parts

This paper presents an approach to predict high cycle fatigue behavior of shot-peened parts based on the multi-axial high cycle fatigue criteria of Crossland and Dang Van. The induced shot peening modifications on the surface layers, which are: (i) in-depth profile of compressive residual stresses, (ii) superficial work-hardening, (iii) surface finish imperfections, (iv) superficial defects, have been taken into account. This approach has been applied to a case of a shot-peened ductile steel SAE 3415 using two conditions: (i) a standard condition of 100% coverage (ii) a severe condition of 1000% coverage (high exposure time). This approach allows to evaluate all the effects of the induced shot peening modifications at the surface and in deeper layers. Good agreement has been observed between the predicted results and those obtained from experimental investigations. A computational procedure has been proposed to predict either high cycle fatigue strength enhancement or degradation of shot-peened parts.