Numerical simulation of residual stress field induced by laser shock processing with square spot

Abstract

Laser shock processing (LSP), also known as laser peening, is a novel surface treatment technique in the past few years. Compressive residual stresses which imparted by LSP are very important for improving fatigue, corrosion and wear resistance of metals. Finite element analysis (FEA) simulation using ABAQUS software has been applied to predict residual stresses induced by LSP on Ti-6Al-4V titanium alloy with laser pulse duration 30 ns and water confined ablation mode. The residual stress field generated by different shape laser spots was studied, and the square laser spot is shown the most suitability for avoiding stress lack phenomenon and overlapping LSP. Surface residual stresses and plastically affected depth within single square spot both increased with the increase of laser intensity and laser shock times. Furthermore, compared with circle and ellipse spot, the residual stress distribution in overlapping square spots is very uniform only with small overlapping ratio. LSP with square spot can process advantageous residual stress field, and this technique will be used widely.