The calculation of in-plane equivalent elastic parameters of a grid beetle elytra plate core

To study the mechanical properties of beetle elytra plates (BEPs) with numerical and theoretical methods, this paper selects the basic unit according to the periodicity of the core layer of grid beetle elytra plates (GBEPs) and establishes an equivalent model of the GBEP core layer. The equivalent Young's modulus and equivalent Poisson's ratio of the unit are obtained on the basis of structural mechanics and the energy method. Compared with the results of finite element method (FEM) simulation, the calculation results of this equivalent model are sufficiently accurate when lambda 1 (the ratio of the cylinder radius to the wall thickness of a core unit) is within a certain range. Compared with the case of the grid plate (GP) core unit of the same size, the elastic parameters of the GBEP core unit show no superiority when buckling is not considered. The in-plane equivalent Young's modulus of the GBEP core unit can reach 7 times that of the honeycomb core element of a similar size, and the larger lambda 1 is, the higher the GBEP core unit performance. In this paper, an equivalent model of GBEPs is established and compared with GPs and honeycomb plates (HPs) in FEM and theoretical analysis, laying a foundation for the application of the equivalent model in FEM analysis.