Finite element analysis of the deformation process in high impact hammering

To study the process of metallic deformation on a high-impact hammer machine, an elastoplastic dynamic-explicit finite element analytical program was developed, based on continuum mechanics. In the program, the inertia was introduced in the equilibrium equation, to analyze inertia effects on high-impact deformation, and hammer velocity was calculated according to the energy method. The resulting FEM program was used to study the deformation process of OFHC copper when struck by a high-speed hammer. The deformation of the billet, the distribution of displacement, and the effective plastic strain in the work-piece were investigated. Simulation results were compared with those obtained by the program without taking account the inertia effect. Subsequently, the effect of changing parameters of hammer speed, strain energy, and impact load were obtained through simulation. The results show that deformation is mainly present on the impacted surface of the specimen, due to inertial effect, and the load in the lower body of the die lags behind that in the upper part of the die at the initial stage of deformation owing to stress wave propagation. The improved FEM program can successfully simulate the metallic deformation process of high-impact hammering.