FEM Simulation of Two Sided Laser Shock Peening of Thin Sections of Ti-6Al-4V Alloy

Abstract

Laser shock peening (LSP) is a fatigue enhancement surface treatment for metallic materials. The key beneficial characteristic of LSP is the presence of compressive residual stresses mechanically produced by shock waves within the metallic materials, which can significantly improve their fatigue life and fatigue strength. During LSP, a laser beam can be directed to impact on either one side or two sides of a target. Generally, when treating a thin section, two sided peening is used to avoid harmful effects such as spalling and fracture, which may occur when only one side of a thin section is laser peened. The present work focuses on applying the finite element method to predict the distribution of residual stresses along the surface and depth of thin sections of a Ti-6Al-4V alloy in single and multiple LSP. In order to understand the effects of the target geometry on the distribution of residual stresses, the residual stress profiles corresponding to various target thicknesses were carefully evaluated. Residual stresses and dynamic stresses were also presented and correlated with experimental data from the literature.