In-plane deformation behavior and energy absorption characteristics of a straight-arc coupled auxetic metamaterial inspired by arch bridges

Abstract

The microstructure and material properties of auxetic honeycomb metamaterials significantly influence their deformation behavior and energy absorption. Inspired by the arch bridge, new types of straight-arc coupled structure (SACS) and the reverse SACS (R-SACS) auxetic metamaterials are designed to enhance the energy absorption capacity (EAC). The quasi-static compression and dynamic impact responses of honeycomb metamaterials are studied numerically under large deformation. A theoretical model is further developed to estimate the average platform stress (σp) of the R-SACS honeycomb, which is verified by the numerical results. For R-SACS--3 with Nylon 12 and Al-alloy, the relative errors of the finite element model compared with the theoretical model are − 5.56 % and − 3.21 %, respectively. Two kinds of basic materials, Nylon 12 and Al-alloy, are employed to analyze the deformation mode of the SACS and R-SACS honeycomb with the same geometric parameters under quasi-static load and impact load. The influence of basic material is discussed, and the structure with Al-alloy exhibits more stability owing to segmented deformation. The creation of additional plastic angles shows an improved σp and specific energy absorption (SEA) compared to the re-entrant structure (RES). σp and SEA of SACS are both 1.3 times as much as those of RES. The peak stress of the R-SACS cellular metamaterial is always smaller than the SACS under impact load, and the maximum reduction is 63 %, which has better a buffering effect.