Mechanical properties of 2D hierarchical re-entrant cellular structures with Voronoi sub-structures

摘要

In this study, 2D hierarchical re-entrant cellular structures with Voronoi substructures were proposed. Their Poisson's ratios and energy absorption capacities (in-plane) were studied using the finite-element method. The effects of geometric parameters (Voronoi sub structure irregularity, k, concave angle, theta, ratio of cell wall thickness to cell height, omega) on the lattice mechanical properties were investigated. Results showed that Poisson's ratio first decreased and then increased with an increasing theta when k is less than 0.5. A minimum Poisson's ratio of approximately 0.315 was achieved when k = 0.5 and theta = 60 degrees. The 2D hierarchical re-entrant lattice structure exhibited a maximum energy absorption capacity when k = 0.2 and omega = 1/3, which is 3.9 times higher than that of the traditional re-entrant structure with solid ribs and of identical relative density. Copyright (C) EPLA, 2018