Numerical and experimental investigations on biomimetic -material: stomatopod dactyl club

The smashing stomatopod, Odontodactylus scyllarus, has been known for its heavily smashing blow creating the velocity and acceleration equivalent to a 0.22 caliber bullet with the forces up to 1.5 kN and the load-bearing part of its raptorial appendages, so-called dactyl club, having a capability of withstanding such tremendous forces. The focus of this research is on this extraordinary damage tolerant dactyl club. The dactyl club is mainly characterized by mineralized fiber layers resembled as a helicoidal arrangement. In this study, the helicoidal composite is the design of biomimetic material and is fabricated by 3D-printing prototype and glass fiber–epoxy composites. The mechanical testing, computational modeling, and theoretical analysis based on linear elastic fracture mechanics on this hierarchical structure are performed to unlock the secrets in this biological material. The experimental results have shown the toughening mechanisms within this hierarchical material as well as the twisting pattern of the fracture. A theory of twisted crack has been developed to explain such mechanism and the numerical simulations are carried out as the verification