A new hybrid auxetic structure capable of uniform deformation exhibits excellent energy absorption

Abstract

As a kind of mechanical metamaterial, auxetic honeycomb with negative Poisson's ratio has received extensive attention in recent years. In order to further improve the stable deformation and energy absorption of the auxetic structure, we combined the asymmetrical re-entrant honeycomb with the triangular honeycombs to propose a new two-dimensional (2D) auxetic structure named asymmetrical re-entrant triangular honeycomb (ART). By setting up comparative experiments, quasi-static compression tests for ART and two existing honeycomb structures (re-entrant star-shaped honeycomb and re-entrant hexagonal honeycomb) along in-plane directions were conducted. A series of ART configurations with different parameters were established, and finite element simulation was used to explore the effects of parameters on the mechanical properties of ART. The unilateral horizontal maximum strain (UHMS) is cited to assess the deformation stability of the structures. The experimental and simulation results show that the deformation of ART is uniform in both in-plane directions. In the compressive strain range that we studied, the specific energy absorption of ART in both directions can be up to 291% and 271% higher than that of the existing structures, respectively, providing excellent load-bearing and energy absorption. In addition, the mechanical properties of ART can be adjusted by changing the geometrical parameters to provide ideas for structural design.