Fibre helicoidally rounding hole of tumblebug's elytra and extrusion strength of biomimetic composite.

Scanning electron microscope (SEM) observation shows that tumblebug's elytra are a kind of chitin fibre reinforced biocomposite. In the biocomposite, the chitin fibres possess a laminated microstructure and distribute in a kind of particular helicoidal pattern. More careful observation indicates that there is a kind of fibre helicoidally rounding hole in the elytra. Based on the SEM observation, a kind of composite laminate with biomimetic fibre helicoidally rounding hole was fabricated through a special mould and moulding process. The extrusion strength of the biomimetic fibre helicoidally rounding hole was investigated and compared with that of the conventional drilling hole in the composite laminate. It is shown that the extrusion strength of the biomimetic fibre helicoidally rounding hole is markedly larger than that of the conventional drilling hole. [ABSTRACT FROM AUTHOR]