In situ determination of the extreme damage resistance behavior in stomatopod dactyl club

Abstract

\n The structure and mechanical properties of the stomatopod dactyl club have been extensively studied for its extreme impact tolerance, but a systematic, in situ, investigation on the multiscale mechanical responses under high-speed impact has not been reported. Here we reveal the full dynamic deformation and crack evolution process within projectile impacted dactyl using combined fast 2D x-ray imaging and high resolution ex-situ tomography We show hydration states can result in significantly different toughening mechanisms inside dactyl under dynamic loading. We find a previously unreported 3D interlocking structural design in the impact surface and impact region using nano x-ray tomography (nano-CT). Experimental results and dynamic finite element modeling (DFEM) suggest this unique structure plays an important role in resisting catastrophic structure damage and hindering crack propagation. Our work will help to understand the key toughening strategies of biological materials and provide valuable information for biomimetic manufacturing of impact resistant materials in general.