Dynamic crushing behavior and energy absorption of hybrid auxetic metamaterial inspired by Islamic motif art

Auxetic honeycomb structures are promising metamaterials with outstanding mechanical properties, and can be potentially used in energy absorption applications. In this study, novel modified re-entrant hybrid auxetic metamaterials inspired by Islamic motif art are designed by integrating four-pointed double re-entrant motifs with symmetric semi-hexagonal unit cells to achieve a high energy absorption capacity (EAC). Theoretical analyses and numerical simulations are performed to examine the dynamic crushing behavior of the four-pointed double re-entrant combined structure (FDRCS). The developed finite element models (FEMs) are validated by the experiments under quasi-static compression. The deformation mode and stress-strain curves are further studied under low, medium, and high crushing velocities. The theoretically predicted plateau stress of the FDRCS under different crushing velocities is consistent with the numerical simulation results. The crushing stress and the EAC of the FDRCS are influenced by the geometric parameters and crushing velocities. The FDRCS exhibits a negative Poisson's ratio (NPR), owing to the four-point re-entrant structure. Moreover, the specific energy absorption (SEA) of these structures is higher than that of nonauxetic hexagonal and auxetic re-entrant structures, owing to the generation of more plastic hinges that dissipate more energy during dynamic crushing.