Metamaterials as transducers for structural health monitoring

Abstract

Structural health monitoring (SHM) has traditionally relied on distributed sensors, data acquisition systems, signal transmission, and external data processing to assess the condition of engineering structures. Although this sensor-centric paradigm enables reliable damage detection, it remains limited by system complexity, wiring, power consumption, maintenance, and scalability. Recent advances in metamaterials offer an alternative approach in which the material itself participates in sensing by transducing structural responses into measurable information through its engineered architecture. This review examines how architected metamaterials encode, transform, and communicate structural information for next-generation SHM. Recent developments are organized according to the physical domain of the generated information: visual information, including shape transformation, structural color, mechanochromism, and mechanoluminescence; electromagnetic information, including electrical, capacitive, piezoelectric, triboelectric, radio-frequency, metasurface, and passive wireless responses; and wave information, including elastic-wave propagation, bandgaps, resonance shifts, mode conversion, localization, and mechanical filtering;. Enabling technologies, including inverse design, topology optimization, additive manufacturing, machine learning, and digital twins, are highlighted for developing multifunctional metamaterials capable of sensing, filtering, amplifying, and communicating structural information. Finally, future opportunities and challenges are outlined for material-centric SHM, in which architected materials evolve from passive structural components into intrinsically intelligent systems that physically process and communicate information before they reach conventional electronic systems.