A three-dimensional simulation of shot peening process using multiple shot impacts

Shot peening is a complex cold-working process involving many disciplines of static and dynamic elasticity and plasticity. The experimental evaluation of shot peening mechanism is very difficult and costly. On the other hand, numerical simulations allow a parametric study of shot peening process and provide an insight into the mechanism, subject to the selection of an appropriate material model and numerical procedure. LS-DYNA code was employed for the numerical simulation in this work. The modeling of shot peening process was accomplished by simulation of multiple shot impacts on a target plate at different velocities. From the simulations, the compressive residual stress profiles were obtained and the effects of velocity and peening coverage were investigated. The results showed that, residual stress distribution was highly dependent on impact velocity and multiplicity. A uniform state of stress was achieved at a particular shots number which was found to be 25 in this work. The shots number corresponding to the state of uniform stress was not the same as that related to the maximum compressive residual stress which may occur at lower number of shots. Impact velocity significantly influences the residual stress profile. The increase of velocity improves the residual stress distribution up to a particular point. Further increase in the velocity may reduce the maximum residual stress. A close agreement between the numerical residual stress profiles obtained in this work was achieved with the experimental profiles reported by Torres and Voorwald.