The Combined Effects of Blast and Fragment Impacts on Textiles

Explosion protection of Personal Protective Equipment is a widely discussed topic in the Defence sector albeit largely misrepresented experimentally. Oversimplified STANAG 2920 single-impact tests and unregulated field blast tests with limited repeatability and ambiguous results, hinder a comprehensive understanding of the problem: the synchronised impact of fragments and a blast wave on a given target. A laboratory experimental setup capable of simulating the combined effects of blast and fragment impacts of a wide range of explosive devices at a defined stand-off distance from a target is developed. A single 1.1g FSP is ejected using a 5.56mm weapon system; tautochronously, a blast wave is generated in an explosives driven shock tube. The two loads are synchronised based on a predetermined simulated stand-off distance. Aramid dry fabrics are tested in different combinations of fragment impacting velocity, blast overpressure and time interval between the two loads, to evaluate their fragment impact resistance in the presence of blast. The tests reveal a time-dependent material ballistic resistance, influenced positively or negatively by the material's oscillating phase. The blast overpressure/impulse acts as an amplifying factor, exacerbating the synergistic effects observed at different time intervals.