A SHOCK TUBE UTILIZED TO PRODUCE SHARPRISING OVERPRESSURES OF 400 MILLISECONDS DURATION AND ITS EMPLOYMENT IN BIOMEDICAL EXPERIMENTATION. Technical Progress Report

A shock tube employed for blast biology studles is described along wlth the results of one series of experiments. The shock tube ls air-driven and utilizes Mylar plastlc dlaphragms. The compression chamber ls 17.5 ft in length and 40.5 ln. ID; it reduces in dlameter to 23.5 in. over a 3-ft-long transition sectlon just upstream of the diaphragm station. The expansion chamber consists of 30 ft of 23.5 in. lD tubing followed by 22 ft of 40.5 in. ID tubing. It is closed dlstally by a steel end-plate to generate high pressures from the reflected shock. Three vents ln the expanslon slde of the system serve to control the duration of the overpressure and to eliminate multiple reflections by bleeding off the reflected shock as it travels upstream. An interspecies correlation is presented based on mortality data from six species of experlmental anlmals with an extrapolation to a 70 kg animal. (auth)