Application of nano-indenter for investigation of the properties of the elytra cuticle of the dung beetle (Copris ochus Motschulsky)

The nanomechanical properties of the multilayer elytra cuticle of the dung beetle (Copris ochus Motschulsky) were investigated in the vertical and transverse directions using a nano-indenter. The reduced modulus E_v and hardness H_v of the surface cuticle in the vertical direction obtained by nano-indentation were 3.54plusmn0.12 GPa and 0.20plusmn0.01 GP, respectively. The nano-indentation result showed that the reduced modulus E_t and hardness H_t of each layer were gradually reduced from the outer layer to the inner layer in the transverse direction. E_v was less than the largest E_t presented at the outer layer (7.06plusmn0.54 GPa). It was supposedly formed as a result of the composite effect of the multilayer. Without consideration of the anisotropy of chitin, an experimental model was proposed to describe the nanomechanical properties of the elytra cuticle