Compressive response of lattice structures: a multiscale approach to model the influence of internal defects

This paper presents a multiscale strategy for modeling the degrading influence of internal defects on the compressive mechanical response of an octet truss lattice structure produced by Powder Bed Fusion and made of AlSi10Mg alloy. Starting from micro-CT scans of a 2 × 2 × 2 lattice structure, the internal defects population is determined and Finite Element Analyses (FEAs) are performed on Representative Volume Elements, i.e., the strut with internal defect, to determine the effective stress–strain response for each defect size. The stress–strain curves are used as material response randomly assigned to each element of the FE model of the lattice structure. By randomly varying the location of the defects within the specimen, the scatter of the compressive response can be accounted for. The effectiveness of the proposed approach is shown by comparison with the experimental results of compressive tests on 2 × 2 × 2 and 3 × 3 × 3 lattice specimens.