Modeling loading rate effect on crushing stress of metallic cellular materials

A mesoscale numerical model based on Voronoi tessellation is developed to investigate the loading rate effect on the crushing stress of cellular materials. The crushing stresses at both the impact and stationary ends of the Voronoi structures are simulated. The influences of the impact velocity, specimen size, inertia, and rate dependence of the base material on the crushing stress are discussed. The underlining reason for the argument on the rate dependence of cellular materials is clarified by comparing the current simulation results with the numerical results based on a continuum model and a shock wave theory. The conflicting observations from previous experimental studies on the dynamic behavior of cellular materials by different researchers are explained by the simulation results as well as the shock wave theory.