Redistribution of Residual Stress Field in the Weld Joint Due to Laser Shock Processing

In this paper, residual stress and plastic damage in the welded joint processed by laser shock processing are investigated. Plastic damage during laser shock processing (LSP) is modeled combined with Gurson-Tvergaard-Needleman (GTN) plastic damage constitutive equations. In order to verify the FEA model, benchmark simulations are performed and verified with available experimental results. Results show that predicted residual stresses agree well with the experimental data. It is very interesting that welding tensile residual stress can be modified and changed into compressive residual stress due to laser shock processing. Simulations reveal that void volume fraction (VVF) referring to ductile damage of materials is approximately constant and decaying sharply at the edge of the impact zone in radial direction. A point can be noted that the magnitude of surface void volume fraction (VVF) increases with increasing power density.