V50 Ballistic Performance of Unidirectional Woven Basalt Fiber Laminated Composites

Abstract

Ballistic fabrics made from high performance fibers such as para-aramid (synthetic) and basalt (natural) fibers, and composites utilizing these fabrics, are among the leading materials for soft body armor systems. Modern military and other law enforcement operations are technology-driven with weapons and ammunition that demand a flexible, damage- and moisture-resistant, and lightweight ballistic fabrics with superior energy absorbing capacity. Basalt fibers, which are extracted from igneous volcanic rocks, are natural fibers with mechanical and thermo-physical properties that are generally comparable or superior to glass and other synthetic fibers at a lower cost. This gives basalt-based composites an edge over contemporary materials for potential application as anti-ballistic body armor. The aim of the present study is to experimentally determine the V50 performance and penetration resistance of unidirectional woven basalt fiber laminated composites with three different combinations of ply orientations [0°, 45° and 90°] at both CW and CCW directions and number of layers namely, B1 (7 layers), B2 (12 layers) and B3 (16 layers). The V50 performance test was conducted in accordance to the MIL-STD-662F standard using the Universal Test Gun (Prototypa UZ-2002). The V50 ballistic velocity is computed based on a minimum of six shots including three complete penetrations (CP) and three partial penetrations. The MIL-STD-662F standard stipulates that the value of ballistic limit protection should be less than 38 m/s for the purpose of computing V50. The V50 value for sample B1, that yielded to CP at 192 m/s and 172 m/s clean through to the witness plate, could not be determined. The V50 for samples B2 and B3 are 117 m/s and 153 m/s, respectively. The optimum number of layers of the basalt fabric to sustain the reference penetration velocity of 367 m/s corresponding to threat Level II of the NIJ Standard-0101.04 is calculated for each specimen for further study. The tensile properties and Shore-D hardness levels of the three samples are also measured and reported.