Influences of inertia and material property on the dynamic behavior of cellular metals

Cellular metals are widely used in light-weight structures and energy absorption devices. Although many experimental studies on the dynamic behavior and rate sensitivity of cellular metals have been reported in the literature, there are some conflicting conclusions on the rate effect of metallic foams. In this paper, some numerical tests are presented to explore the effects of inertia, strain hardening and strain-rate hardening of the cell wall material on the behavior of Voronoi honeycomb samples under dynamic compression. Three deformation modes are found and corresponding nominal stress-strain curves and the plateau stress of the "specimens" are obtained. The results reveal that inertia plays an important role in Shock Mode and Transitional Mode but it does not affect the compressive stress-strain curve of the honeycomb. The strain-rate sensitivity of the honeycombs is less significant than that of the cell-wall material and becomes negligible under high impact velocities. The strain-hardening effect of the cell-wall material is of less importance.