Topology Optimization and Additive Manufacturing of Customized Sports Item Considering Orthotropic Anisotropy

Topology optimization is a shape optimization method connected with finite element (FE) structural analysis, and has recently received increasing attention owing to rapid evolution of additive manufacturing (AM). In this study, a rifle support for the sport biathlon is developed by combining three-dimensional (3D) scanning, FE analysis, topology optimization, and AM. Considering that the biathlon requires a stable shooting motion under hard breathing after a distance of cross-country skiing, the rifle support was designed to be fitted to a human body based on 3D scanning data. Topology optimization was then performed to reduce the part weight efficiently, and its structural safety and stiffness were evaluated by FE analyses considering the orthotropic material properties and the relevant printing directions. The optimized design and printing direction were showed 12.7% improvements in the specific stiffness and 23–43% improvements in the structural safety according to the direction. The final design was fabricated using a fused deposition modeling type 3D printer with acrylonitrile butadiene styrene filament. Compression tests were then performed to evaluate its structural safety, and the resulting relative critical force showed a 40% improvement in comparison with the original design.