The effect of trabecular chamfers on the compressive ductility of beetle elytron plates

Beetle elytron plates (BEPs) are a type of sandwich structure inspired by the internal architecture of beetle elytra and characterized by trabeculae (tube structure) in the core. BEPs are categorized into two types, end- and middle-trabecular BEPs (EBEPs and MBEPs, respectively), according to the trabecular position. Both have been shown to possess superior compressive strength relative to conventional sandwich plates. To further improve the compressive ductility of the BEP, the mechanical effect of the trabecular chamfer inspired by the Allomyrina dichotoma beetle elytron is experimentally investigated. The results are as follows: 1) Only the EBEP stress-strain curve can form a plateau, which means better compressive ductility. 2) Various buckling modes are produced in BEPs with different β (ratio of core height to wall thickness) and ξt (ratio of chamfering radius to trabecular radius); however, the compressive ductility is significantly improved only when full global buckling deformation is generated in the core of the EBEP. 3) In the present condition, only when ξt is not less than 1.5, global buckling can be generated in EBEPs with a larger range of β, and the ductility improvement effect can also be better utilized. These results reveal the mechanism of the chamfering effect and parameter range previously found in Allomyrina dichotoma elytra, which facilitates further optimization of the compressive property of the BEP.