Sustainable natural fiber-reinforced hybrid composites as energy-absorbing layers in multilayered armor systems: A structured review

Composite systems based on natural fibers have attracted renewed attention in the search for lightweight, sustainable, high-performance ballistic armor. This review presents a comprehensive, hierarchically classified overview of critical performance parameters associated with the use of natural fibers for ballistic applications, focusing on fiber systems and hybridization strategies, failure mechanisms, and energy-absorption characteristics. Special focus is given to natural–natural hybrid composites, as well as to the correlations among fiber structure, interfacial properties, and mechanical performance, including ballistic behavior. Through a structured literature review of relevant data within a verified benchmarking framework for structure–property–performance relationships, the review characterizes the dominant design drivers of energy dissipation, penetration resistance, and back-face signature reduction in multilayer armor systems. The work also illustrates that new interfacial engineering and machine learning methods can facilitate the design of advanced protective materials. In general, these results demonstrate that natural-natural hybrid composites lay the scientific foundation for lightweight, sustainable, and high-performance armor systems, as well as a platform for optimizing these materials.