Effect of Resin Content on the Mechanical and Ballistic Performance of B4C/Aramid III/UHMWPE Ceramic Composite Armor with Comparative Evaluation of Fiber Architecture and Manufacturing Process

This study investigates the effects of resin content, fiber architecture, and manufacturing process on the mechanical response and ballistic behavior of Aramid III/epoxy support layers used in B4C ceramic composite armor. Three plain-woven Aramid III/epoxy laminates containing 20 wt%, 30 wt%, and 38 wt% resin were fabricated and characterized in terms of density, porosity, flexural properties, interlaminar shear strength, and low-velocity impact response. In addition, unidirectional (UD) and plain-woven laminates with a fixed resin content of 30 wt% were compared to clarify the influence of fiber architecture, while autoclave and hot-press processing were compared in terms of internal porosity and structural uniformity. The results showed that the 30 wt% resin laminate exhibited the lowest measured porosity (0.3%) and the best overall balance of flexural strength, flexural modulus, and impact-energy absorption, with values of 421 MPa, 34.6 GPa, and 141.5 J, respectively. The UD laminate exhibited a 38.5% higher impact-energy absorption than the corresponding plain-woven laminate, demonstrating the influence of continuous fiber alignment on load transfer and impact deformation. The autoclave process produced lower porosity than hot pressing for the 30 wt% laminate, indicating improved consolidation and microstructural uniformity. Ballistic tests were conducted on the plain-woven support-layer configurations using 12.7 mm armor-piercing incendiary projectiles under identical nominal areal density and impact conditions. The 30 wt% configuration achieved protection in all four tests and exhibited a mean back-face signature of 11.25 mm, compared with protection success rates of 50% and 75% for the 20 wt% and 38 wt% configurations, respectively. Post-impact characterization revealed B4C fragmentation, fiber deformation, matrix cracking, interlaminar delamination, and deformation of the UHMWPE backing layer. These results indicate that an intermediate resin content provides a favorable balance between interfacial load transfer and fiber deformation within the investigated armor configuration. The effects of fiber architecture and manufacturing process are also discussed as important factors affecting the structural and mechanical response of the support layer.