Hierarchical crossed‐lamellar structure in conch shells: Mechanics and biomimetics

Conch shells, featuring a highly mineralized hierarchical crossed‐lamellar structure that epitomizes the pinnacle of molluscan evolution, possess remarkable strength and toughness to protect their soft bodies from predatory attacks. Understanding the mechanical behavior of conch shells can offer valuable insights for the development of high‐performance biomimetic structural materials. In this review, we provide a comprehensive overview of the development in the mechanics and biomimetics of conch shells with crossed‐lamellar structures over the past five decades. We discuss the advances in the mechanical properties and toughening mechanisms of conch shells, as well as the numerical modeling and theoretical models of crossed‐lamellar structures. We also present the progress in the development of biomimetic materials with crossed‐lamellar structures, such as cellulose‐based composites, ceramic composites, and polymer composites. Finally, we discuss significant challenges and future trends in the mechanics and biomimetics of conch shells. This review is expected to offer a modest spur to induce others to come forward with valuable contributions to the further development of both the mechanics of hierarchical crossed‐lamellar structures and high‐performance biomimetic materials.