Abstract: To improve the mechanical properties of Trabecular Beetle Elytron Plates (TBEPs, a type of biomimetic sandwich structure inspired by the beetle elytron) under transverse loads, three-point bending tests are performed to investigate the influence of the trabecular and chamfer radii of the core structure on the mechanical performance of TBEPs manufactured by 3D printing technology. The results show that the three-point bending performance of TBEPs can be improved by setting reasonable trabecular and chamfer radii; however, excessive increases in these radii can cause a decline in the mechanical performance. For the reason, these two structural parameters can enhance the deformation stiffness of the whole structure and the connection property between the core and skin, which is also the mechanical reason why Prosopocoilus inclinatus beetle elytra have thick, short trabeculae with a large chamfer radius. However, when these radii increase to a certain extent, the cracks are ultimately controlled between two adjacent trabeculae, and the failure of the plate is determined by the skin rather than the core structure. Therefore, this study suggests a reasonable range for trabecular and chamfer radii, and indicates that TBEPs are better suited for engineering applications that have high compression requirements and general bending requirements.

Key words: beetle elytron, bio-inspired structure, sandwich structure, honeycomb plate, trabeculae, bending properties