Fatigue life prediction of scratch damaged shot peened components

Abstract

PurposeThis paper aims to present a methodology, based on traditional approaches, to predict the fatigue life and non‐propagating cracks of shot peened components and the damaging effect of a scratch created over the treated surface.Design/methodology/approachThe finite element method is used to determine the actual strain at surface and fracture mechanics parameters calculated from cracks at the surface. The model considers residual stress (in order to introduce the effect of shot peening) and the scratch geometry. The total fatigue life is obtained by adding initiation life, to early and long crack propagation life using appropriate criteria.FindingsNumerical predictions were compared with previous experimental tests, showing that this method is quite reliable for predicting both fatigue life and non‐propagating cracks of shot peened components, including the effect of damage due to a scratch.Research limitations/implicationsThe proposed method provides good results and a clear understanding of the fatigue process, however it requires a considerable amount of both material and shot peening parameters.Practical implicationsThe methodology presented in this paper allows the determination of fatigue life and the prediction of non‐propagating cracks for components, including the effects of shot peening and scratch damage. These results can be used to quantify the scratch damage limits of components improved by shot peening.Originality/valueThis paper provides a useful tool for prediction of the effects of shot peening and scratch damage on fatigue life, using traditional approaches.