Experimental and numerical analysis of a bolted reinforced honeycomb with tunable Poisson's ratio

Abstract

The use of large honeycomb structures is becoming increasingly widespread, with many specialized honeycomb structures being produced through additive manufacturing and laser cutting technologies. However, the high manufacturing costs and low efficiency associated with these methods limit their applicability. In this paper, reinforced honeycombs with a total length of nearly 1 m were assembled using bolts. The effects of relative thickness and corrugated plate angle on Poisson's ratio and mechanical properties were investigated both experimentally and numerically. Additionally, three design strategies - layered, internal and external, and space filling - were adopted to further regulate Poisson's ratio. The results show that relative thickness, angle, and the aforementioned design strategies can all be used to regulate Poisson's ratio. As the thickness of the reinforced plate increases, energy absorption (EA) increases, but specific energy absorption (SEA) decreases. The reinforced honeycomb structure (RHC) exhibits the best energy absorption and SEA at a 60° angle. Through hierarchical, internal, and external designs, this paper shows that the reinforced honeycomb structure with one layer of reinforcement plus one layer of non-reinforcement (1+1-RHC) has the largest negative Poisson's ratio effect. Furthermore, the transition structure between RHC and 1+1-RHC is studied through unreinforced space filling design. The fabrication method presented here promises low-cost and large-scale fabrication with the ability to program Poisson's ratio, making it suitable for applications in protective gear and smart energy absorbing devices.