Mechanical reinforcement mechanism of a hierarchical Kagome honeycomb

A hierarchical Kagome honeycomb with triangular sub-structures (KHT) is proposed in this study. KHT is constructed by introducing hierarchical configurations to conventional Kagome honeycomb. The theoretical model is established to analyze the compressive behaviors in terms of plateau stress and specific energy absorption (SEA) based on two-scale analysis method. Compared to the conventional Kagome honeycomb (KH), subjected to y-direction loading, the improvement of mean crushing force (MCF) and SEA of KHT is up to 104% and 83%, respectively. The remarkable enhancement on crashworthiness induced by the hierarchical configuration is demonstrated by the theoretical spectrum. The predicted plateau stress and SEA show high agreement with the simulated results. The mechanical reinforcement can be further realized by tailoring the topology and the number of sub-structures and the structure relative density. Subjected to the increasing impact speed, the reinforcement generated by the hierarchical design is gradually eclipsed by the inertial effect. The reinforcement mechanism is explicitly revealed from the aspects of macroscopic wall interactions and microscopic sub-structures collapse patterns. This study provides insight and opportunities into the role of structural hierarchy in designing hierarchical honeycombs equipped with extraordinary energy absorption properties.