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

Additive manufacturing offers new design opportunities in employing lattice structures for lightweight appli-cations. Especially, conformal lattice design can be made with internal lattice core with freeform external ge-ometry. 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 trans-formation 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 me-chanical performance than the uniformly in-filled counterparts. This work provides the first quantitative cor-relation 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.

Automated summary

Additive manufacturing allows for the use of lattice structures in lightweight applications, particularly conformal lattice designs with freeform external geometry and internal lattice cores. However, the mechanical properties of conformal lattices are not well understood. This study used triply periodic minimal surface (TPMS) based conformal shell lattices fabricated by laser powder bed fusion (LPBF) to investigate the influence of design factors on mechanical properties. The results showed that factors such as shape transformation type, tilting angle of side walls, and cell orientation greatly influenced the deformation mechanism and mechanical properties of the shape-transformed structures. Additionally, the study found that the boundary between misaligned shape-transformed TPMS did not affect mechanical properties and energy absorption capability, and that conformal TPMS-filled monoclastic lattice exhibited better mechanical performance compared to uniformly in-filled counterparts. This work provides a quantitative correlation between design factors and mechanical properties of shape-transformed structures, highlighting the potential of TPMS-based conformal design in real-world lightweight applications.