A 3D FE model with plastic shot for evaluation of equi-biaxial peening residual stress due to multi-impacts

A 3D multi-impact finite element (FE) model for evaluation of peening residual stress is presented. Combined peening factors by Kim et al. are applied to the 3D symmetry-cell originally contrived by Meguid et al. To describe the feature of multi-impacts, concepts such as FE peening coverage, impact sequence and cycle-repetition are introduced. We successfully extracted the equi-biaxial stress from the simulations of diverse single-cycle and multi-cycle impacts. At four impact locations of FE symmetry-cell, surface and maximum residual stresses converge to equi-biaxial stress, and convergence improves with the number of repetitions of cycle. Impact velocity needed for comparing the FE solution with the XRD result is determined from the Almen arc height and coverage. It is further found that the simulation set with plastic shot produces residual stress consistent with the experimental XRD result.