Design of non-uniform three-dimensional star-shaped concave lattice structures via metal additive manufacturing for high energy absorption and lightweight applications

Lattice structures are increasingly utilized for lightweight applications and impact energy absorption. Advances in additive manufacturing enable precise control over their geometry and mechanical properties, facilitating the creation of complex, lightweight designs. This study focuses on optimizing non-uniform lattice structures, which distribute material according to applied load conditions, outperforming uniform designs by enhancing mechanical properties like impact energy absorption while preserving lightweight characteristics. This work designed three star-shaped lattice unit cells with varying Poisson’s ratios, including negative values, and investigated their mechanical properties. Using finite element analysis, a non-uniform lattice structure was developed by strategically integrating these unit cells. Impact tests conducted with a Split Hopkinson Pressure Bar compared uniform and non-uniform lattice structures, confirming the superior energy absorption capabilities of the latter. The practical engineering potential of this approach was demonstrated through an energy absorption box designed for real-world applications. This research underscores the importance of non-uniform lattice designs, leveraging unit cells with tailored Poisson’s ratios, in achieving efficient, lightweight energy-absorbing solutions for engineering purposes.