Energy Absorption and Impact Response of Meta-lattice Truss Core Sandwich Panels

Abstract

A novel and original meta-lattice truss core sandwich structure, which combines the concepts of lattice sandwich structures and elastic metamaterials, is proposed and designed for impulsive attenuation and mitigation. This new type meta-lattice truss core sandwich structure has similar configurations as a normal lattice sandwich panel, but its truss bars are consisted of meta-lattice truss unit cells. The design philosophy of locally resonant elastic/mechanical metamaterials is integrated into the meta-lattice truss unit cell, where a relatively heavy metal core (the resonator) is coated by a soft material layer, then connected by a heavy outer shell. Based on this combination, several bandgaps are created by the local resonant behavior of the designed microstructures at particular frequencies of an impulsive wave, where the stress wave cannot propagate and energy is largely absorbed. The comparisons of responses between normal and meta-lattice truss core sandwich panels subjected to impulsive loadings are analyzed. The origins and mechanisms of energy absorption are also systematically investigated. Results evidently reveal that more superior ability of impact mitigation is achieved by the proposed new type structures; and higher energy absorption capability are caused by the local resonance of resonators and soft coats at different band-gap frequencies.