Parameter optimisation analysis of laser shock processing based on Ansys LS-Dyna

Abstract

Laser shock processing (LSP) treatment of Q345 steel under various parameters (peak pressure, spot diameter, number of shocks and laser pulse width) was simulated with Ansys LS-Dyna by using a variable-controlling approach to optimisation. It can be concluded that the influence of LSP on surface roughness is proved to be quite weak according to the simulation results of surface morphology. The influence of different parameters on LSP is discussed based on the residual stress field distribution of the model. The optimal effect can be achieved with a single LSP impact at a peak pressure of 3–4 GPa. By increasing the spot diameter, the residual stress field is improved mainly on the top surface, but feebly in depth. Given the hardening phenomenon of the target material, the residual stress field tends to be saturated after three impacts. Thus, three LSP impacts is the most reasonable number, and the best effect can be achieved at a laser pulse of 30 ns.