Development of conformal shell lattices via laser powder bed fusion and unraveling their mechanical responses via modeling and experiments

Abstract

Additive manufacturing offers new design opportunities in employing lattice structures for lightweight applications. Especially, conformal lattice design can be made with internal lattice core with freeform external geometry. However, the mechanical response of conformal lattices is not well understood. In this work, triply periodic minimal surface (TPMS) based conformal shell lattices were designed based on isoparametric transformation method and fabricated by laser powder bed fusion (LPBF) to study the influence of key design factors on the mechanical properties of the conformal shell lattices. The results show that the deformation mechanism and mechanical properties of the shape-transformed structures are highly influenced by design factors including shape transformation type, tilting angle of side walls and cell orientation. The boundary between the misaligned shape-transformed TPMS does not deteriorate the mechanical properties and the energy absorption capability. Finally, conformal TPMS-filled monoclastic lattice was studied to verify the effectiveness of the conformal design for mechanical applications. It is found that the conformal TPMS-filled monoclastic lattice shows better mechanical performance than the uniformly in-filled counterparts. This work provides the first quantitative correlation between the design factors and the mechanical properties of the shape-transformed structures and highlights the potential of TPMS-based conformal design for real-world lightweight applications.