AN ANALYSIS OF STRESS CONCENTRATIONS CAUSED BY SHOT PEENING AND ITS APPLICATION IN PREDICTING FATIGUE STRENGTH

Abstract

Abstract— In order to calculate the stress concentration caused by shot‐peening dents, three simplified models, namely a one‐pit model, a seven‐pit model and a pit‐loop model, are proposed in this paper. By using a finite element program for automatic dynamic incremental non‐linear analysis, the stress concentration coefficients based on these models are calculated for different pit parameters and different stress fields. When considering the stress concentration and residual stress field produced by shot peening, a modified Goodman formula is proposed and used for forecasting the fatigue strength of peened specimens having the fatigue sources at the surface. The forecasted results were verified by peening followed by fatigue tests on 40Cr steel.