Ballistic Performance of Ceramic/S-2-Glass Composite Armor

Ceramic composite armor was initially developed during the Vietnam War for use as helicopter armor and personnel armor. The requirements for the armor were light weight and the capability to defeat small caliber armor piercing (AP) projectiles. Several different ceramics were developed and tested for this application. It was found that aluminum oxide (Al2O3), silicon carbide (SiC) and boron carbide (B4C) had the best combination of properties to meet the requirements. The long term goal of this research is to develop domestic knowledge, design and production capability of ceramic composite armors. In this present research, the relationship between the ballistic performance and mechanical properties of ceramic armor composites were investigated. The armor composite consisted of a 100x100 mm(2) commercial monolithic ceramic front tile; i.e. sintered Al2O3, sintered SiC, or hot-pressed B4C bonded with an S-2-glass reinforced polymer composite (GRPC) backing plate. The ballistic test was performed against 7.62 mm projectiles (M80 Ball) in the velocity range of 800-970 m/s. A linear correlation between the areal density of armor and the V-50 results was illustrated. The V-50 ballistic limit values for the Al2O3, SiC and B4C composite armors, calculated via U.S. Mil-Std-662F, were found to be 913 m/s, 869 m/s, and 829 m/s, respectively. High-speed photographic images captured during ballistic testing revealed the transition from dwell to penetration by the 7.62 mm projectiles. The complete penetration of all the armor composites was found to have occurred in approximately 200 microseconds. Furthermore, the relationship between the volume of the cone crack and mechanical properties were examined. The fracture toughness values of Al2O3, SiC, and B4C were 4, 4.6, and 2.9, respectively. The volume of the cone cracks formed on the ceramic front tile plates increased with an increase in the fracture toughness of the ceramic materials.