The Thoraco-Abdominal Systems's Response to Underwater Blast

Abstract : The purpose of this study was to model the response of the thoraco-abdominal system to underwater-blast waves. The effort focused on the dynamics of submersed gas bubbles because previous studies had shown that most injuries occurred to the gas-containing organs and the immediately adjacent tissues. Experiments were conducted to obtain data for use as input in the development of a model. Gas-containing balloons, excised organs (swim bladders, gut sections and sheep lungs): excised organs (swim bladders and gut sections) in gelatin blocks; and whole animals (fish and rats) were viewed with high-speed cameras while being exposed to a shock wave in an underwater test chamber. Overpressure vs time was measured inside the thoraces and abdomens of sheep exposed at either of two depths to underwater blast in a test pond. Both the film and gauge records indicated that the gas bubbles enclosed in the various submersed objects underwent damped oscillations. In general, the measured frequencies and amplitudes of oscillation were shown to be consistent with the theory of spherical air bubbles undergoing adiabatic changes in free water.