Exploring a modular adaptive metastructure concept inspired by muscle's cross-bridge

The multifunctionality and versatility of skeletal muscle is a worthy inspiration towards the development of engineered adaptive structures and material systems. Recent mechanical modeling of muscle suggests that some of muscle's intriguing macroscale, passive adaptivity results from the assembly of nanoscale, cross-bridge constituents that maintain multiple metastable configurations. Inspired by the new observations, this research explores a concept of creating modular, engineered structures from the assembly of mechanical, metastable modules, defined as modules that exhibit coexistent metastable states. The proposed integrated systems are termed metastructures: modular, engineered structures exhibiting unprecedented characteristics resulting from a synergy of the constituents. Analytical and experimental results demonstrate that when modular metastructures are prescribed a global shape/topology, the systems may yield significant and valuable properties adaptivity including variation in reaction force magnitude and direction, numerous globally stable topologies, and orders of magnitude change in stiffness. The influences of important parameters on tailoring the displacement range of coexistent metastable states are investigated to provide insight of how the assembly strategy governs the intriguing versatility and functionality which may be harnessed.