Mechanical characterization of a novel gradient thinning triangular honeycomb

Abstract

Negative Poisson’s ratio (NPR) structures have attracted much attention in last decades due to its excellent energy absorption ability, and introducing functional gradient into the structures is able to further improve the anti-crushing behavior, thus this work proposed a novel gradient thinning triangular (GTT) honeycomb by varying its layer number which exhibited the NPR effect under compression. The elastic modulus, strength, Poisson’s ratio and energy absorption of the GTT honeycomb were fully characterized by employing theoretical analysis, mechanical tests, digital image correlation (DIC) technology, and numerical simulation. Moreover, the modulus-, strength- and energy absorption-efficiencies were evaluated. The result showed that under constant material consumption, the elastic modulus, yield strength, energy absorption, modulus efficiency and strength efficiency were decreased as the layer number increased, but the Poisson’s ratio and energy absorption efficiency (energy absorption per mass) were optimized at the two-layer GTT honeycomb. Specifically, the maximum energy absorption efficiency of the two-layer GTT honeycomb was 1.7 times that of the conventional triangular honeycomb, and this illustrated that the properly-designed two-layer GTT honeycomb could more effectively absorb energy under constant materials mass with respect to other GTT honeycombs. This finding could be helpful to design novel energy-dissipating materials to maximize anti-crushing ability in industrial applications with prescribed materials mass, such as shock-proof corrugated plate in packaging engineering.