Numerical modeling of residual stress field for linear polarized laser oblique shock peening

Abstract

To deal with the oblique laser shock situation for some complex structure workpieces, the shock wave pressure model is established for different shock angles and different laser polarization states according to the laser parameters. The laser energy loss when passing through the water layer is calculated in this model. The finite element method is applied to analyze the distribution of residual stress in surface and depth directions after LSP. The surface topography and residual stress are measured by experiment at different shock angles and different laser polarization states. The results show that the pit depth gradually decreases as the shock angle increases, and the pit depth of orthogonal polarized laser shock peening is smaller than the parallel polarized laser shock peening. The degree of difference is especially obvious when shock angle exceeds 30°.With the increase of the shock angle, the surface residual stress increases first and then decreases. The influence depth of compressive residual stress decreases with the increase of the shock angle. The residual stress changes for the orthogonal polarized laser oblique shock with the angle is in keeping with parallel polarized laser oblique shock, but the rate of the residual stress reduce is faster. The residual stress hole problem can be solved by choosing the appropriate shock angle in some cases.