Analytical and numerical analyses are carried in order to reveal the importance of the topology of the cellular materials for their dynamic compaction. The aim is to distinguish between the deformation mechanisms and energy absorption of materials, which exhibit structural softening, such as out-of-plane loaded honeycomb, and structural hardening (foam). It is shown that the dynamic compaction of honeycombs does not obey the law of shock wave propagation and a new phenomenological model of the velocity attenuation in out-of plane loaded honeycomb is proposed. Comparisons with some currently available theoretical models of the dynamic compaction of cellular materials are discussed when paying attention to the effect of the material homogenization of the honeycomb on their response to impact loading.
A numerical analysis of a bi-layer cellular structure comprising layers with dissimilar constitutive properties is carried out to reveal the possibility for the peak load reduction in cellular structures when subjected to impact loading. In the reported examples, a foam material (Alporas with density of 245 kg/m3) and hexagonal honeycomb made of aluminium alloy AA5056 and having densities of 60.46 kg/m3 and 96 kg/m3 are used.
