Advances in smart and multifunctional composite materials: design, mechanisms, and applications

Intelligent and multifunctional composite materials have transitioned from passive structural systems to adaptive platforms that can sense, actuate, convert energy, and self-repair. Nonetheless, despite its expansion, the domain remains disjointed. Mechanisms, manufacturing methods, and performance measurements are frequently examined in isolation, hindering the transition to dependable engineering systems. This review rigorously assesses contemporary smart composite designs by linking functional mechanisms with interface engineering, manufacturing scalability, and long-term dependability. It demonstrates that several documented high-performance systems depend on laboratory-specific circumstances, but practical implementation is hindered by conflicting property requirements, interfacial instability, and environmental degradation. This review’s distinctiveness lies in creating a cohesive framework that connects multiscale modelling, sophisticated manufacturing, and multifunctional performance evaluation to discern design trade-offs rather than focusing solely on material enhancements. Current advances, such as artificial intelligence-assisted material discovery, programmable metamaterials, structural energy storage, and bio-inspired designs, are evaluated in terms of manufacturability and durability rather than solely functional output. Special emphasis is placed on novel sustainable composites and digital-twin-enabled predictive maintenance. Significant hurdles persist in scalable manufacturing, consistent multifunction integration, power management, and lifetime stability under cyclic loads and adverse conditions. Resolving these difficulties necessitates integrating material design with system-level optimisation and standardised assessment methodologies. This paper offers a prospective framework for advancing smart composites from experimental materials to reliable engineering components in aircraft, robotics, healthcare, and energy infrastructure.