On the rate sensitivity of metallic cellular solids

This paper aims at investigating the rate sensitivity of metallic cellular materials. It begins with a review of likely causes responsible for the strength enhancement of cellular materials, which include the rate sensitivity of the base material, the effects of the pressure of the air entrapped in the cell, the inertia effect, and the shock enhancement. Then, a recently developed testing method using 60 rum diameter nylon Hopkinson pressure bars with suitable signal processing is presented. Applications of this Hopkinson bar technique allow for experimental investigations on the rate sensitivity of various metallic cellular materials, i.e. 5 056, 5 052 aluminium honeycombs of different cell sizes and wall thickness, IFAM and Cymat aluminium foams as well as the sintered steel hollow spheres.