Effect of Inertia on the Dynamic Behavior of Cellular Metal

Although the mechanical property of metal foams has been widely studied, there are some conflicting conclusions on the strain-rate effect and the inertia effect of metallic foams. For a deep understanding of the role of inertia in the dynamic response of cellular metals, finite element method is used to study the dynamic compression of 2D Voronoi honeycombs. Three deformation modes are formulated. Numerical experiments are conducted by changing the density of wall material and the impact velocity. Corresponding macroscopically-averaged stress-strain curves measured on the impact surface and support surface and the plateau stress of the specimens are obtained. According to the simulation results, the influence of inertia is analyzed. It is found that the inertia of the honeycomb has no effect on the stress-strain curve as the macroscopic deformation is homogeneous. However, the inertia effect will result in nonuniform deformation as the impact velocity is high, and thus the plateau stress is obviously increased.