Dynamic response of gradient cellular materials under high velocity impact

The dynamic behavior of gradient cellular materials subject to high velocity impact is investigated theoretically and numerically. A parameter refined rigid-perfectly-plastic-locking model is developed and employed in the one-dimensional shock-wave theory to predict the response of gradient cellular materials under high velocity impact. The finite element analysis is carried out based on the periodic Voronoi structure and shows good agreement with the analytical prediction. The dynamic response and energy absorption are examined for different gradient cellular rods with the same mass and length but different density gradient. It is found that, at the first part of the high velocity impact crushing process, the cellular rods with negative density gradient show higher energy absorption ability and lower pressure at the distal end compared to the positive and uniform ones. This advantage can be taken when the partial crushing happens and vanishes when the cellular rods are fully crushed. (paper)