Fatigue failure prediction in lattice structures through numerical method based on de-homogenization process

Metal lattice structures from additive manufacturing (AM) processes are promising solutions for the design of lightweight components and therefore several strategies for their static modeling are available. However, the high concentration of notches, combined to the surface roughness typical of AM as-built conditions, make lattice structures very vulnerable to fatigue failures. Furthermore, the evaluation of stress and strain in cellular materials is very challenging due to the geometrical complexity and the associated computational heaviness of numerical models. In this paper, the authors present a numerical method based on the homogenization and de-homogenization processes to determine the expected fatigue lifetime of the lattice component. The method requires limited computational effort by limiting the estimation to the most loaded cell, which is considered as representative volume element (RVE) to establish the multi-axial fatigue loads.