Numerical Study of the Shape Irregularity Gradient in Metallic Foams Under Different Impact Velocities

The properties of metallic foams are closely related to the average pore size, relative density and degree of the shape irregularity in the meso-structure. In this paper, gradient metallic foams with Voronoi structures based on different degrees of shape irregularity are constructed and numerically tested under different impact velocities. We combine three types of metallic foams with identical relative density but different degrees of shape irregularity in a specific sequence (from large to small or from small to large) to construct the new gradient models. A series of impact tests at different velocities are performed on the gradient metallic foams to acquire deformation characteristics and stress states. According to the results from the inertia effect and the energy absorption capacity, a gradient metallic foam with a shape irregularity that changes from large to small (negative gradient) is the optimal design. The simulation results provide a fresh perspective and methodology to design gradient metallic foams at the meso-structure scale for use as energy absorption materials.