Automatic Design of 3D Conformal Lightweight Structures Based on a Tetrahedral Mesh

Abstract

Recent developments of additive manufacturing (AM) have extended its application to the direct fabrication of functional parts. Owing to design flexibility and complexity, design for AM (DFAM) has received increasing attention as a new design method that can overcome traditional manufacturing constraints, and has been applied to multi-components integration, multi-material parts, and lightweight structures. In this study, an automatic design methodology for conformal lightweight structures was developed based on a three-dimensional (3D) tetrahedral mesh. A numerical algorithm was developed to generate lightweight cellular structures via the following steps: (i) definition of a target solid; (ii) discretization of the target volume using a tetrahedral mesh; (iii) construction of a number of struts along the edges of every tetrahedral element; (iv) Boolean operation to unify the generated struts; and (v) preparation of output files for 3D printing and finite element analysis (FEA). This algorithm was then applied to generate conformal cellular structures with various shapes. Effects of lattice design parameters on the relevant density change were discussed. The designed cellular structures were then fabricated by AM, and their mechanical properties were evaluated by compression tests. The fabricated lightweight structures showed high specific stiffness and strength, and could support 10000 times heavier load than their own weight.