Sensors to Assess Pressure-Mediated Effects on Blast-Induced Traumatic Brain Injury
Annual rept. 15 Feb 2008-14 Feb 2009
NAVAL MEDICAL RESEARCH CENTER SILVER SPRING MD
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This study was designed to investigate the contributions of direct impact of blast on the skull in two different orientations face-on and side-on orientation. To assess a loading force on a target with different impact areas two piezoelectric PCB sensors were placed inside a shock tube in parallel and perpendicular orientations to the blast wave. Results show that the face-on pressure is much higher than the static, side-on pressure. In addition, the integral area under the pressure wave increases with the target size as a consequence of pressure wave reflection with increasing target. Rats were placed in a blast tube and exposed to 30-40 kPa blast overpressures in two different orientations 1 with the head facing the blast wave, and 2 with one side of the body exposed to the blast. Pressure waves inside the rat brain and lateral cerebral ventricle was measured simultaneously with Samba pressure microsensors and compared with the outside pressure waves. Pressure wave characteristics such as rise time, duration, and amplitude were found to differ with respect to the orientation to the blast. Characterization of the shock wave after blast produced in the shock tube was achieved by installing two piezoelectric sensors inside the shock tube. The basic characteristics of the blast wave measured by fiber optic pressure sensors was similar to the piezoelectric sensors. This justifies the use of microfiber sensors for animal experiments. Shock wave after blast was detected simultaneously in two locations of the rat brain, and in two different orientations to the blast wave. The results show some differences that could be very important for understanding the mechanisms of pressure wave propagation and penetration into the brain and the mechanisms of brain blast injury.
- Medicine and Medical Research
- Weapons Effects (Biological)
- Fluid Mechanics