Study on residual stress of laser shock processing based on numerical simulation and orthogonal experimental design

Abstract

Laser shock processing (LSP) is a competitive alternative surface enhancement process. Shock pressure with high magnitude and short duration induced by LSP is one key parameter to induce a residual stress field in the material. Finite element method (FEM) simulation based on the orthogonal experimental design is adopted to analyse the interaction of different shock pressure profiles with the material. It can give a relatively accurate description of the effect of shock pressure profile on the residual stress field induced in the material with a representative coverage of all parameters by less calculation cost. The analysis results show that laser shock conditions should be selected carefully to ensure a favourable shock pressure to obtain an optimised residual stress field. The simulation on the overlapping laser shock is also presented and indicates that it is an effective method to settle the residual stress drop on the top surface and can obtain a much more favourable residual compressive stress field to enhance the fatigue resistance of the material.