Effect of Cross-Section Designs on Energy Absorption of Mechanical Metamaterials

Numerous studies have examined various geometric designs in cellular structures, yet the role of cross-sectional geometry remains underexplored. Cross-sections significantly influence the effective material properties of architected materials, where stress concentrations at junctions can reduce structural strength. This study investigates how different cross-sections affect energy absorption efficiency in both bending- and stretching-dominated cellular structures. Five classes of lattice structures, each designed with four distinct cross-sections, were fabricated using a custom stereolithography printer. Mechanical performance—specifically energy absorption and energy absorption efficiency—was evaluated through physical simulation and experimental testing. The results show that selecting optimal cross-sections can enhance yield stress by an average of 35% for cubic, 39% for BCC, 22% for BCCZ, and 41% for FCC structures. These findings demonstrate the critical impact of cross-sectional geometry on mechanical behavior. Both experimental and finite element analysis-based homogenization approaches were employed to validate results. The study proposes cross-section design guidelines aimed at optimizing strength-to-weight ratios, offering valuable insights for the development of high-performance mechanical metamaterials.