Simulation of the elasto-plastic response and residual stresses near metal surface due to laser shock processing

摘要

Laser shock processing (LSP) is now emerging as a viable surface treatment technique to improve the fatigue, corrosion and wear resistance and the mechanical properties of the metals through introducing the deep compressive residual stresses into the materials. The aim of the present paper is to address the elasto-plastic response and the residual stresses in the metal alloy 35CD4 50 HRC steel due to single and multiple LSP with a square laser spot by using the finite element analysis. The simulation is composed of two distinct parts, namely the dynamic analysis and the subsequently static analysis. The history of the changes of the residual stress and deformation of the material can be clearly reflected in these analyses. Results show that the predicted results for single LSP agrees well with the available experimental data. Meanwhile, the effects of multiple LSP processes, pressure magnitude and duration, and laser spot size on the compressive stress field and the plastically affected depth in the target are evaluated. Some optimalized parameters can be selected through the present parametric study. Hence, the present research might provide some important insights on the parameter optimization in LSP.