Analytical and numerical modeling on strengths of aluminum and magnesium micro-lattice structures fabricated via additive manufacturing

Abstract

Bioinspired lattice structures have a wide range of applications in aerospace, automotive, energy, and medical device industries due to their high strength-to-weight ratio. Although experimental and numerical modeling methods have been extensively used to characterize the compressive behavior of lattice structures, an accurate analytical model has great values in material/structure designs and applications. In this study, a new analytical model is developed for two configurations based on limit analysis in the plasticity theory to predict the compressive strengths of micro-lattice structures (MLS). The model is also discussed for determining the amounts of stretching-dominated deformation and bending-dominated deformation. A comparative study is performed between analytical solutions and experimental results of AlSi10Mg (aluminum alloy) and WE43 (magnesium alloy) MLS additively manufactured via selective laser melting (SLM). Finite element simulations using beam elements are conducted to evaluate the accuracy of the analytical solution. Analytical results, finite element simulation results, and the experimental results are in a good agreement with both AlSi10Mg and WE43 MLS. The shear band formation, as a main failure mode of MLS, is also studied and evaluated using the classical Rudnicki–Rice’s criterion, for which a reasonably good accuracy is demonstrated.