Numerical simulations of mechanical peening of titanium alloy

Mechanical peening is based on striking a worked material surface by hard balls (shot).In this work, a pneumatic method, applied for double-sided shot peening of the worked sample surface, was selected. The samples were made of the titanium alloy WT3-1 (Ti-6Al-2Cr-2Mo). The described work consists of two parts. The laboratory experiment was conducted in first part. After it realization, various observations were conducted. Observations of surface topography for samples were carried out before and after shot peening using scanning electron microscope (SEM). They revealed quite regular plastically deformed zones generated due to applied working. Neither microcracks, spallings nor delaminations in deformed surface layer of the titanium alloy were observed which attests to correct technological process of the surface hardening. The numeric simulation of the peening process was conducted in part second. The physical model described non-simultaneous impact of three steel balls onto rectangular metal sheet made of the above-mentioned titanium alloy. Numerical FEM analysis for nonlinear dynamics (explicit) was carried out using LS-Dyna software (Livermore Software Technology Corporation). In the paper are presented maps of the material effort in surface layers for times corresponding to conditions after impacts of the first, second, and the third ballof cast steel shot.