Competing energy absorption and shape recovery in 3D-printed composite meta-honeycombs under cyclic compression

This study investigates the cyclic compressive behavior of 3D-printed composite meta-honeycombs, focusing on the trade-off between energy absorption and shape recovery. Three configurations, hexagonal (HEX), auxetic re-entrant (ARE), and double arrow-head (DAH), were fabricated using Nylon and Onyx and tested under quasi-static cyclic compression in both in-plane and out-of-plane directions. Key metrics, including specific energy absorption (SEA), undulation of load-carrying capacity (ULC), shape recovery ratio (SRR), and energy dissipation ratio (EDR), were used to quantify repeatable energy absorption and recovery performance. Results reveal a pronounced competition between crashworthiness and recoverability. Fiber reinforcement enhances stiffness, strength, and SEA but reduces shape recovery, highlighting a material-level trade-off. SEA is generally higher under out-of-plane loading, while in-plane SRR is 25–35 % greater than the out-of-plane SRR, showing strong sensitivity to loading direction. Cyclic compression at different deformation stages leads to stage-dependent degradation, with SEA reductions of approximately 10 %, 50 %, and 100 % during the elastic, plateau, and densification stages, respectively. Finite element simulations elucidate configuration-dependent deformation mechanisms and support the experimental observations. This study establishes the universality of the trade-off across material systems, topologies, loading directions, cyclic stages, and provides quantitative insights for designing reusable energy-absorbing honeycomb structures.