Geometry-driven W-plated Kevlar composite armor for balancing flexibility and ballistic resistance

The high specific strength, low density, and excellent energy-absorption capability of Kevlar ® fibers have enabled the design of low-mass and highly flexible body armor systems. However, contemporary body armor is restricted to either flexible, lightweight systems with limited structural reinforcement or rigid, monolithic plate-based configurations offering higher ballistic resistance at the expense of mobility. The present work addresses this issue by investigating the development of a composite Kevlar segmented-plate architecture with a W-plated structural geometry inspired by medieval lamellar armor designs. An extensive exploratory proof-of-concept is achieved via the development of complete prototype body armor systems, and subjecting their segmented composite plate components to quasi-static compression and ballistic testing based on a modified National Institute of Justice (NIJ) 0101.06 Level IIA protocol using six 9 mm, 124 gr full metal jacket projectiles fired at five reduced-scale specimens at velocities of approximately 365 m/s. The W-plated specimens exhibit negligible backface deformation of less than 1 mm, meeting the NIJ 0101.06 specification of less than 44 mm, with zero projectile penetrations, whereas the flat lamellar comparison specimen exhibited 57 mm of backface deformation. In subsequent controlled compression testing, W-plated specimens sustained a mean maximum load of 13.61 ± 1.35 kN versus 1.12 ± 0.10 kN for flat controls, a 12.2-fold difference. Microstructural analysis indicates that fiber integrity and interlayer bonding are preserved after testing. Collectively, these findings provide preliminary evidence supporting geometry-driven composite armor architectures balancing flexibility, lightweight systems, and ballistic protection.