NUMERICAL SIMULATIONS OF SHOT-PEENING PROCESS AND IMPACT EFFECT

The shot-peening process and impact effect were simulated by using software LS-DYNA. Propagation and interaction of stress waves in the treated material were analyzed based on numerical simulation results. The stress wave structure, high strain-rate effect and attenuation of stress wave were also investigated. The overlapping ratio between shots was studied and the high peening coverage model was established. The effects of impact sequence, material strain-rate and initial residual stress on the residual stress and the surface deformation were examined. The results indicate that the hi-h strain-rate induced by shot impact is related to the elastic and plastic wave structure. The surface quality is essentially affected by overlapping ratio and its approximate critical value is found to be 1/2. The effect of impact sequence can be neglected, but the strain rate plays an important role in determining the level and distribution of the residual stress field. The influence of original residual stress in the target is significantly dependent on the impact velocity. The shallow pocket in depth is induced on the top surface of material by multiple impacts, and the surface deformation increases with the increase of impact time.