Grid octet truss lattice materials for energy absorption

Abstract

Octet truss lattice material, the most well-known stretching-dominated lattice material, is attracting attention in lightweight material engineering. Low resistance to buckling loading limits its use in lightweight energy absorbers. Here, we propose a new strategy to construct octet truss lattice materials with high mechanical properties and stable nonlinear compression response at low relative densities. The effective mechanical properties of the generated grid octet lattice materials have been investigated both numerically and experimentally. Results show that the relative elastic modulus, yield strength and specific energy absorption will increase with either the relative density or the number of the grid structure. At a relative density of 0.5 and compared to the truss lattice, the gain in Young’s modulus, yield strength, and SEA is 26%, 26% and 25%. Respectively. Additional compression test on the 316l stainless steel samples demonstrates introducing triangular grid structures suppresses the post-buckling behavior of the octet lattice. The generated grid octet lattice materials possess a nearly constant plateau stress between initial yield and densification, even at a relative density of about 0.2. The designed lattice material is thus a noteworthy alternative for load bearing and energy absorption.