Amplification of Air Shock Waves by Textile Materials

The peak reflected pressure measured under a flexible and porous textile material exposed to air shock waves may increase by an order of magnitude over the case where no material is present. This peak pressure amplification is a result of the development of shock waves in the two phase (solid/air) material as a result of the low equilibrium sound speed in porous materials and the increase in density of the materials during the transit of the shock wave. This peak pressure amplification may increase the lung injury severity for humans with layered textile materials covering their torso who are exposed to strong air shock waves.

The dynamics of shock wave propagation and reflection in flexible and porous textile materials were studied both analytically and experimentally by using an air driven shock tube. A numerical model of the human chest-lung system was adapted for evaluating the effects of different textile materials covering the human chest. Experimental shock tube results were input to the computer model of the human chest to allow a comparison between the different textile materials.