Dynamic impact response and energy absorption performance of conch shell-inspired cross-laminated metamaterials

Addressing the inherent defects of traditional body-centered cubic (BCC) lattices, which are highly prone to rapid, global catastrophic failure and dangerous stress localizations under dynamic impact, and profoundly inspired by the naturally occurring, highly toughened cross-layered microstructures found in seashells, this paper aims to develop a novel class of protective metamaterials that seamlessly combine extreme lightweight characteristics with highly efficient dynamic energy absorption capabilities. Based on the utilization of advanced high-toughness resin materials, a single-layer bionic structure featuring node-constrained spatial gradients and a sophisticated three-layer bionic cross-layered metamaterial employing an orthogonal stacking strategy were meticulously designed, with the traditional uniform BCC lattice serving as the baseline control group. Low-velocity dynamic impact tests were rigorously conducted using an advanced drop-weight impact testing system. This experimental approach was systematically combined with in-situ high-speed photography and highly detailed explicit dynamic finite element simulations to comprehensively compare and analyze the complex deformation responses, stress wave propagation patterns, and progressive failure evolution processes of the three distinct topologies under transient dynamic loading. The multifaceted results reveal that the traditional lattice exhibited rapidly penetrating global shear bands and highly destructive rigid bottoming phenomena, severely limiting its protective utility; the single-layer bionic structure significantly enhanced the initial impact-bearing capacity through engineered mechanical heterogeneity, but an overall structural softening still inevitably occurred in the later stages of large deformation; conversely, the three-layer bionic structure, precisely through interlayer orthogonal rotation, successfully constructed a macroscopic artificial interface, effectively triggering a profound interface-blocking effect and greatly increasing the tortuosity of crack propagation pathways. The study concludes that this multidimensional bionic collaborative design fundamentally transforms the failure mode of the three-layer metamaterial into a highly desirable progressive crushing mechanism, distinctly characterized by a beneficial interlayer deformation lag. Ultimately, this hierarchical structure effectively eliminates hazardous bottoming peaks and reliably maintains a prolonged, stable load plateau even under extreme compression, exhibiting exceptional impact kinetic energy dissipation performance and providing a robust new paradigm for the future design of advanced, lightweight impact-resistant and energy-absorbing structural systems.