Mechanical behaviors of SLM additive manufactured octet-truss and truncated-octahedron lattice structures with uniform and taper beams

In this paper, three-dimensional lattice structures composed of octet-truss and truncated-octahedron unit cells with regular and tapered beams are proposed, and their mechanical properties are investigated through experiments and simulation comparisons. Firstly, analytical closed form expressions of the relative density functions are derived for different lattice structures. Secondly, in-situ compression samples are fabricated via Selective Laser Melting (SLM) 3D printing technique, monotonic compression experiments are performed for studying the effects of tapered beams on the mechanical properties of lattice structures with ordinary uniform beams, and SEM characterizations of fracture surface morphology are performed for understanding the underlying failure mechanisms. Afterwards, asymptotic homogenization (AH) method is used for evaluating the anisotropy properties of these lattice structures, closed form expression of the mechanical behaviors of unit cells is derived and solved with ABAQUS® using surface traction method. Asymptotic homogenization analysis shows that node enforcement can significantly enhance the modulus and reduce the anisotropy of the lattice.