Out-of-plane compression performance of 3D-printed eco-friendly sandwich plates inspired by beetle elytra microstructures

Owing to their excellent strength-to-weight ratio, honeycomb sandwich structures have long been favored in impact mitigation and energy absorption applications. Integrating wood-plastic composites into 3D-printed bioinspired sandwich designs offers a sustainable path toward enhanced mechanical performance. In this study, the out-of-plane compressive behavior of two 3D-printed bioinspired configurations, traditional honeycomb plate (HP) and end-trabecular beetle elytron plate (EBEP), was systematically investigated using both experimental testing and finite element simulations. The sandwich plates were fabricated from polylactic acid (PLA) and a PLA-based composite reinforced with wood fibers (PLA/WF). Results demonstrate that the incorporation of wood fibers significantly improves both the specific load-bearing capacity and specific energy absorption of the structures, with EBEP showing greater performance gains than HP. Microstructural analysis reveals that the performance enhancement stems from multiple reinforcement mechanisms contributed by the wood fibers. The close agreement between experimental and simulation results confirms the reliability of the proposed model and sheds light on the reinforcing role of wood fibers. These findings offer theoretical support for the development of cost-effective and eco-friendly high-performance energy-absorbing structures.