Modeling of residual stress field induced in Ti-6Al-4V alloy plate by two sided laser shock processing

Two sided laser shock processing (TSLSP) is often employed to improve the surface quality of thin section components, which can reduce excessive plastic deformation induced by one sided laser shock processing. Residual stresses (RS) field induced in a thin Ti-6Al-4V alloy plate by TSLSP was investigated through numerical simulation and experiments. The effects of key parameters, viz., metal plate thickness, shock wave pressure and number of laser shocks, on RS field were analyzed. The simulation results show that the RS field induced by TSLSP was distributed symmetrically in the metal plate. For thin sections, compressive residual stresses (CRS) were found to exist on the surface of both the sides and also in the mid-plane region, whereas, for thick sections, CRS were found to only distribute on the surface of both the sides. The multiple TSLSP impacts and the increasing laser shock pressure were found to have significant effects on the RS field. The RS values predicted by the model correlated well with the experimental data.