Emerging acousto-mechanical metamaterials: From physics-guided design to coupling-driven performance

The growing demand for materials that simultaneously absorb airborne sound and sustain mechanical loads has catalyzed the rise of acousto-mechanical metamaterials (AMMs)—architected systems that embed acoustic resonances within mechanically efficient architectures, enabling multifunctionality beyond the reach of conventional materials. This review provides in-depth insights into the structural and physical principles that govern acoustic absorption—the central challenge in advancing AMMs. We classify existing architectures and reveal how tailored topologies can achieve superior resonant responses and dissipative pathways. To overcome causality-governed efficiency–thickness trade-offs, we consolidate three physics-informed enhancement strategies: coherent weak resonator coupling, geometry-driven impedance tuning, and intrinsic loss engineering—offering viable paths toward optimal absorption. Critically, we elucidate the structural origins of acousto-mechanical coupling by analyzing synergistic trends and mismatches arising from parent material, unit-cell scale, and topological interdependence. We introduce a three-tier coupling framework based on geometry-sharing levels, clarifying when acoustic and mechanical functions can be decoupled and when they demand co-optimization. Finally, we outline key challenges and propose future directions in functional integration, AI-driven development, and real-world deployment. Positioned at the intersection of geometry, physics, and multifunctionality, AMMs are poised to serve as a versatile platform for next-generation engineered systems.