Experimental and numerical investigation on lattice structures fabricated by selective laser melting process under quasi-static and dynamic loadings

Abstract

Lattice structures are a class of cellular materials with greater control over the mechanical properties, relative to other common cellular materials like foams and honeycomb structures. In this paper, three lattice structures including Kelvin, Rhombic dodecahedron, and truncated cuboctahedron with identical geometric dimensions in quasi-static and dynamic loadings were investigated to identify the proper lattice structure for impact resistance applications. This study consisted of two experimental and numerical sections. In the experimental section, the lattice structures were fabricated using the selective laser melting (SLM) method from the AISI 316L material. The dynamic tests of the lattice structures were performed by the split Hopkinson pressure bar (SHPB) with a strain rate of 765 s−1. In the numerical section, the modeling was carried out by the finite element method (FEM) to predict the properties of the lattice structures. The results of the experimental tests showed that the selected lattice structures had a high strength to weight ratio and considerable impact resistance; so, they could be suitable for use in lightweight and impact-resistant structures. In addition, the modeling results revealed a good agreement with the experimental results. Finally, the specific absorbed energy of the Rhombic dodecahedron lattice structure in the quasi-static compression test and with the 50% strain was 7% and 15% higher than that of Kelvin and truncated cuboctahedron lattice structures, respectively. While, with evaluation of the dynamic results, the truncated cuboctahedron lattice structure had higher area under the specific stress-strain curve in comparison to the other two structures.