A new stress-driven composite porous structure design method based on triply periodic minimal surfaces

Replacing the solid infills with porous structure infill is a reliable method in the field of 3D-printed model lightweight. Triply periodic minimal surfaces (TPMSs) provide a smooth and fully connected porous structure and can be mathematically described, making itself an ideal infilling structure for lightweight design. In this paper, a design method of composite porous structure based on TPMSs is proposed, which takes the multi-scale bionic porous structure for reference, performs the stress-driven weighted random sampling on the basis of the finite element analysis results, and combines the offset geodesic B-splines with the Geodesic Voronoi Tessellations (GVT). The method can not only optimize the structure by reasonably selecting the inherent parameters of TPMSs, but also can realize the mechanical optimization by controlling the distribution of Voronoi sites and the offsetting weight of the geodesic B-splines based on the stress distribution. Both the Finite Element Analysis (FEA) results and mechanical experiments show that the proposed composite porous structure has better mechanical continuity and 19% lower initial peak stress than the TPMSs basic structure, and has better compressive performance and 48% stronger energy absorption capacity than the lattice structure. Additionally, a mesh fusion optimization strategy is proposed to avoid the stress concentration and improve the structural strength.