An engineering predictive design approach of high cycle fatigue reliability of shot peened metallic parts

It is well-established that the high cycle fatigue (HCF) behaviour is very linked to the surface conditions of the mechanical components, and is significantly characterised by a probabilistic effect. The aim of this work is to develop a model predicting the probabilistic HCF behaviour of shot peened metallic components. The prediction is based on the multiaxial HCF criterion of Crossland. The modifications induced by shot peening in the first outer layers of the treated parts were taken into account. They are classified into four categories: (i) the compressive residual stresses, (ii) the surface work-hardening (iii) the geometrical irregularities and (iv) the superficial defects. The HCF reliability was computed by using the “Strength-Load” method with Monte Carlo simulation. Three types of dispersions have been taken into account: (i) the Crossland criterion material characteristics, (ii) the shot peened surface conditions and (iii) the applied loading parameters. Interesting and useful shot peening iso-probabilistic Crossland diagrams (PCD) can be determined for the different shot peening affected layers. An application has been carried out on a shot peened ductile steel. It has been observed that the shot peening HCF reliability predictions and the obtained PCDs are in a good agreement with the experimental results. This method has been also used to analyse and discuss the influence of the surface shot peening properties on the HCF reliability.