A novel coupling-induced strength-improved three-dimensional honeycomb with positive-negative dual Poisson's ratios

Abstract

By combining the Re-entrant (RE) cell with the hexagonal (HE) cell, this study proposes a novel three-dimensional honeycomb called Re-entrant-hexagonal-coupling (RHC) honeycomb to improve the strength of a single structure. The deformation modes and the strength of the honeycomb are comprehensively investigated through experimental and numerical methods. Results indicate that the deformation of the RHC honeycomb exhibits a clear coupling effect due to the opposite deformation of the RE and HE honeycombs, resulting in a quasi-zero Poisson's ratio mode and a significant strength enhancement. The coupling-induced enhancement (CIE) of the RHC honeycomb remains consistently higher than 0.585, demonstrating clear superiority over the other two comparative honeycombs. Besides, adjusting the thickness ratio can effectively balance the coupling effect and auxetic effect, thereby enhancing the specific energy absorption at a given relative density. This study offers valuable guidance for the design and research of such coupling auxetic honeycomb structures, warranting further attention.