Heterostructured Mechanical Metamaterials Inspired by the Shell of Strombus Gigas

The shells of molluscs have been shown to be strong and tough, despite being highly mineralised, as a result of various types of architectural design that effectively control the development of shear bands and cracks during deformation. The crossed-lamellar design of the shell of <i>Strombus gigas</i>, whose hierarchy consists of four distinct lamellar-shaped features, represents the toughest of all seashells. A mechanical metamaterial that replicates the natural structure of this queen conch is anticipated to circumvent the renowned trade-off between strength-ductility and strength-density. Here we introduce the architectural concepts of dimensional discreteness and interactive discreteness, inspired by the crossed-lamellar design, to instruct the design of bio-inspired metamaterials. Inspired by the crossed-lamellar microstructure, we introduce its three-dimensional hierarchical and interactive architecture concept to instruct the design of bio-inspired metamaterials that mitigate failure from the extension of a single shear band and instead develop numerous smaller bands confined within the individual plank-like zones introduced in their layered geometric design. The results have far-reaching implications for the design of strong mechanical metamaterials from a brand-new perspective.