Harnessing nacre-inspired buckling: Enhanced cushioning in biomimetic staggered composites

Nacre-inspired staggered composites demonstrate exceptional potential for energy absorption applications, yet their buckling-governed mechanical behavior remains insufficiently understood. This study integrating theoretical modeling, experimental validation, and numerical simulations, decodes the buckling mechanics in staggered composites. The asymptotic perturbation analysis of nonlinear governing equations yields an analytical solution for tablet post-buckling in staggered architectures, enabling precise prediction of critical buckling stresses with <5 % experimental deviation. Quasi-static compression tests reveal a well-defined stress plateau with minimal fluctuation (<5 %) in the staggered composites, demonstrating significant potential for cushion applications. Then, a comparative analysis against conventional thin-walled metallic tubes demonstrates superior energy absorption metrics: staggered composites achieve near-unity crush force efficiency and full shape recovery with significant mechanical hysteresis, outperforming metallic counterparts. Further, the impact simulations reveal that the staggered structure achieves superior cushion performance over a broader loading range than metallic thin-walled structures, i.e., corrugated tube and circular tube, leveraging its characteristic post-buckling response. Finally, compared with the existing energy-dissipation materials with recoverable deformation, the Ashby chart suggests simultaneous optimization of specific energy absorption and specific stiffness in staggered architectures. Therefore, the knowledge gained from this study may serve as a novel biomimetic strategy for protective system optimization.