Significance of microstructural defect-tolerant in the battle for survival: Mantis shrimp VS. Nacre

Abstract

Mantis shrimps use their robust claws to repeatedly strike and break the shells of bivalves during predation without sustaining damage themselves. It appears to be a confrontation between the bouligand microstructure and the brick-and-mortar microstructure of the nacre layer. In the daily struggle for survival, defects are inevitably introduced. To elucidate the mechanical mechanisms exhibited by the two microstructures in the struggle for survival, thus a bold conjecture was proposed: the bouligand structure exhibits less sensitivity to random defects compared to the brick-and-mortar structure, enabling mantis shrimps to survive in the battle for existence. To verify this hypothesis, numerical models of bouligand and brick-and-mortar microstructures were established considering interfacial random defects. The results indicated that for various defect volume fraction, the bouligand structure demonstrates superior mechanical performance compared to the brick-and-mortar structure. In terms of peak load and damage dissipation energy, the bouligand structure exhibits higher tolerance to interfacial random defects than the brick-and-mortar structure, delaying the occurrence of damage in the Bouligand structure while prematurely inducing damage in the brick-and-mortar structure. This study not only reveals the mechanical mechanisms behind the advantages of biological microstructures in the struggle for survival but also provides technical references for future biomimetic microstructure designs.