Bioinspired Interlocking Cells - A Programmable and Assemblable Lightweight Materials Platform

Nature frequently inspires advanced engineering solutions through remarkable structural adaptations, such as the interlocking features found in beetles, crabs, and ants, which confer strength, flexibility, and resistance to damage. Inspired by these natural examples, this study investigates bioinspired interlocking metamaterials to enhance structural integrity, adaptability, and ease of maintenance. Two distinct interlocking topologies, square and triangular unit cells, were fabricated using fused-deposition 3D printing of polylactic acid (PLA) and evaluated through standardized mechanical tests, including uniaxial tension, compression, and 3-point bending. Complementary finite element simulations in Abaqus/Explicit were performed to elucidate the underlying deformation and load-transfer mechanisms and to validate the experimentally observed force–displacement responses. The results demonstrate that these biomimetic interlocking structures exhibit tunable stiffness, superior strength, and enhanced durability without requiring permanent fasteners or adhesives—characteristics notably lacking in granular metamaterials, particularly under tensile and bending conditions. Such attributes are especially advantageous for aerospace applications, including unmanned aerial vehicles (UAVs), electric vertical takeoff and landing (eVTOL) aircraft, and general airframe development, addressing critical challenges in lightweight design, structural reliability, rapid repair, and operational versatility. Overall, the proposed interlocking cells establish a programmable and assemblable lightweight materials platform that can be tailored for a wide range of next-generation structural systems.