Mechanistic Elucidation of Dynamic Deformation Transitions and Energy Absorption in Gyroid Structures Across Relative Densities and Compression Velocities.

Understanding the rate-dependent deformation and energy absorption behavior of architected lattice structures is essential for developing lightweight impact-resistant materials. This study investigates the effects of loading rate and relative density on the mechanical response of additively manufactured acrylonitrile butadiene styrene (ABS) gyroid structures. Quasi-static and dynamic compression experiments were conducted, and PAM-CRASH finite element simulations were validated against the experimentally investigated compression conditions and subsequently used to explore responses beyond the experimentally accessible velocity range. The results show that both the initial peak crushing force and mean crushing force increase with increasing relative density and loading velocity, with distinct strengthening characteristics from quasi-static loading to high-velocity impact. Increasing loading velocity induces a transition in deformation behavior from homogeneous layer collapse to localized shear banding and fracture. At 100 m/s, the numerical simulations further predict a transition toward inertia-dominated layer-by-layer collapse. Lower-density structures exhibit higher sensitivity to loading rate, with deformation transitions occurring at lower velocities. Although total energy absorption increases with loading velocity, the specific energy absorption shows limited dependence on relative density under high-velocity loading. These results highlight the coupled effects of loading rate and relative density on the deformation and energy absorption of gyroid structures and provide insights into the design of lightweight lattice structures for impact-resistant applications.