Energy absorption characteristics of rotating mechanical metamaterials

Mechanical metamaterials are artificially designed materials that exhibit extraordinary physical properties absent in conventional materials. Among them, triply periodic minimal surface (TPMS) structures have garnered significant interest due to their unique zero mean curvature geometry and outstanding mechanical performance, making them widely applicable in impact energy absorption for lightweight structures. However, the impact of structural rotation on their energy absorption performance remains underexplored. In this study, three representative TPMS architectures—Primitive, Gyroid, and Diamond—were analyzed through homogenization simulations to determine their directional elastic modulus distributions. Based on the identified anisotropic characteristics, each structure was subjected to rotations toward its strong, weak, and intermediate stiffness directions according to a prescribed rotational strategy. Furthermore, in-plane rotations were introduced within each directional configuration to investigate their effects on energy absorption behavior under quasi-static uniaxial compression. To verify the accuracy of the finite element simulations, six representative TPMS specimens were fabricated using additive manufacturing and tested under quasi-static compression. A comprehensive evaluation was then conducted to assess the influence of different rotational strategies on deformation patterns and energy absorption performance indicators. The results reveal that strategically applying rotational manipulation can significantly enhance the energy absorption performance of TPMS structures, thereby addressing a critical gap in understanding how anisotropy can be exploited to optimize energy-absorbing performance.