Investigation of Ductile Damage Induced by Laser Shock Processing on a 35CD4 Steel

摘要

In this paper, a material ductile model induced by laser shock processing was developed to predict the ductile damage of materials, which refers to carrying capacity reduction of materials during a laser shock processing treatment. Ductile damage of 35CD4 30HRC induced by laser shock processing was investigated by finite element analysis (FEA) method combined with Gurson-Tvergaard-Needleman (GTN) ductile damage constitutive equations. The effects of power density, spot size and full width at half maximum (FWHM) on ductile damage had been discussed respectively. In order to verify the FEA model, benchmark simulation was performed coupled with experiments. The results of the benchmark simulation show similar residual stress magnitude and distribution compared with experimental data. Results reveal that void volume fraction (VVF) in relation to ductile damage of materials is approximately constant, decays sharply at the edge of the impact zone in radial direction and only exists in hundreds of micron near surface in depth. Furthermore, the results demonstrate magnitude of VVF rises with increasing power density or decreasing FWHM, while magnitude of void volume fraction VVF is almost the same when spot size changes.