Citation

Skews BW, Bugarin S, Sawicka E. Int. J. Impact Eng. 2010; 37(3): 231-241.

Copyright

(Copyright © 2010, Elsevier Publishing)

DOI

10.1016/j.ijimpeng.2009.07.005

PMID

unavailable

Abstract

Various injuries to persons result from exposure to explosions or other forms of rapid energy release such as in the vicinity of the firing of artillery. These injuries are classified into three main groups: primary, secondary and tertiary injuries. Primary injuries are caused by the impact of a gas dynamic shock or blast wave on the human body, which mainly affect the gas-containing organs, such as the lungs, abdominal organs and auditory canals. It can result in serious internal injuries, very often with no external indications of trauma. Previous studies of these effects have largely concentrated on the physiological and medical aspects rather than the causative reasons. There have been a number of empirical studies to quantify the effects. A few studies have focused on the physical mechanisms that lead to the pressure amplifications. The current study is an extension of the shock tube experiments to explore the influence of oblique impact of a plane shock wave on a plane or curved surface covered by a layer of textile.

Previous studies of the impact of a blast or shock wave on a layer of textile positioned a short distance in front of a surface have shown that significant pressure amplification can occur. These studies have all dealt with the case of head-on impact on plane textile surfaces. This study extends such work to plane textile specimens inclined to the wave propagation direction, both for the textile freely suspended in order to examine the transmitted wave and with it positioned a short distance in front of a solid surface. Tests are also conducted with the textile suspended in a cylindrical shape positioned in front of a curved surface to approximate a more realistic practical loading case on a torso. Three textile types were used, varying significantly in permeability. In the oblique impact case it is found that the pressure amplification decreases as the wall angle decreases. The behaviour of the wave system in the gap between the textile layer and the body is clarified, showing a succession of oblique shock reflections and transmissions back through the textile layer. Tests on the cylindrical body surface at low Mach number show no significant amplification at the most forward position and steadily decreasing pressure around the sides of the surface. The concern regarding very large increases in pressure which arose from tests on head-on impact on plane surfaces appear to be ameliorated when the body is curved. Computer simulations are used to confirm the wave pattern for the cylindrical case by modeling a curved porous surface a short distance in front of a rigid wall.