Optimal and adaptive lattice design considering process-induced material anisotropy and geometric inaccuracy for additive manufacturing

High-resolution additive manufacturing (AM) facilitates engineering applications of cellular lattices with complex geometries. The unique layer-by-layer process of AM causes the mechanical performance of as-fabricated lattice structures to deviate from the ideal value. In this study, the AM process-induced material anisotropy and geometric inaccuracy are integrated into the mechanical evaluation and topology optimization of lattice structures. Specifically, effective mechanical properties of typical strut-based and shell-based lattices are evaluated by the homogenization method combined with the process-induced features. The equivalent stiffness parameters of ideal and as-fabricated lattices are integrated into the topology optimization algorithm to adaptively obtain corresponding macrostructures. Based on the knowledgebase of unit cells and optimized results, the threshold of the variation for microstructure is extracted to guide design and process parameter selection. The proposed design guidelines and evaluation-adjustment framework can be widely applied to various lattices fabricated by AM technologies.