Combined effects of wrinkled vein structures and nanomechanical properties on hind wing deformation

Abstract

The veins in the hind wings of the Asian ladybird beetle (Harmonia axyridis) play active roles in flight and in the folding/unfolding of the hind wing. Wrinkled vein structures are located within the bending zone and are used for folding the hind wing. This paper investigates the coupled effect of wrinkled vein structures within the hind wing of H. axyridis on its deformation. Based on the nanomechanical properties of the veins, morphology of the hind wing, surface structures of the veins, and microstructures of the cross sections (including the veins and wing membranes), four 3-D coupling models (Model I and Model II: variably reduced-modulus veins with and without wrinkles, respectively; Model III and Model IV: uniformly reduced-modulus veins with and without wrinkles, respectively) are established. Relative to the bending and twisting model shapes, Model I has much more flexibility during passive deformation to control wing deformations. The simulation results show that both the wrinkled structures in the bending zone and the variably reduced modulus of the veins contribute to the flight performance (the bending and twisting deformations) of the hind wings, which has important implications for the design of the deployable wings of micro air vehicles (MAVs).

Keywords: Asian ladybeetle vein; Combined effect; Deformation; Nanomechanical properties; Wrinkled structures.