A review of multifunctional hybrid fiber-reinforced polymer (HFRP) composites for aerospace applications

Hybrid fiber-reinforced polymer (HFRP) composites, composed of two or more distinct fiber types embedded within a common matrix, offer enhanced design versatility compared to conventional counterparts. By integrating different fibers at the strand, fabric, or ply level, HFRP composites mitigate the limitations of individual fiber types while leveraging their respective advantages. In many cases, hybridization induces synergistic effects or yields emergent properties not attainable by either constituent alone, though these effects can be complex and challenging to predict. Recent advancements in hybrid composite architecture have attracted significant attention due to their unique and tunable properties. HFRP composites are increasingly recognized as promising candidates for multifunctional material systems, capable of simultaneously delivering structural integrity with additional functionalities. Non-structural attributes integrated within structural components are especially pertinent in aerospace applications, such as urban aerial mobility, stealth aircraft, space habitats, energy storage, and smart skins. In these applications, properties such as radar avoidance, electromagnetic interference (EMI) shielding, airfoil morphing, health monitoring, thermal insulation and environmental resilience are of paramount importance. This review provides a comprehensive overview of continuous, discontinuous, synthetic and natural fiber hybrid configurations, highlighting recent developments and key contributions in the field. It synthesizes the current state of research on multifunctional HFRP composites, emphasizing integrated functionalities such as electrical and thermal conductivity, sensing, actuation, flame retardancy, degradation resistance, EMI shielding, radiation resistance, damping, self-healing, and de-icing capabilities. The review also discusses current challenges and outlines future directions for advancing the design, manufacturing, and application of HFRP composites in high-performance aerospace systems. A comprehensive review of hybrid fiber-reinforced polymer composites with focus on aerospace applications. Presents recent advances in multifunctional properties including sensing, actuation, EMI shielding, flame retardancy, self-healing, thermal/electrical conductivity, and icing/ de-icing. Discusses how combining distinct fiber types enables emergent synergistic behaviors beyond those of single-fiber composites. Discusses current challenges and future research directions for the design, fabrication, and implementation of multifunctional hybrid-fiber composites in high-performance aerospace systems.