Design and mechanical property studies of 3D re-entrant lattice auxetic structure

A new Ti-6Al-4V 3D re-entrant lattice auxetic structure is designed and manufactured by electron beam melting (EBM) in the present study. 2D structural components are combined into a 3D re-entrant lattice auxetic structure by a new connection and topological method. Under uniaxial loading, all 2D structural components show negative Poisson's ratio and bear loads. Four different configurations were fabricated and tested under uniaxial compression. The structure's deformation mechanisms during the compression process are analyzed. The relationship between the geometrical design parameters and the structure's mechanical properties is deduced by the beam theory. Furthermore, the compression test of the structure is simulated by the finite element method (FEM). It is shown that the theoretical and simulated results are consistent with experiments. Compared with classical re-entrant lattice structure, the new 3D re-entrant lattice structure has better mechanical properties, stronger energy absorption capacity and great larger design scope. The results show guiding significance for the study of 3D re-entrant lattice auxetic structures.