Citation

Goeller J, Wardlaw A, Treichler D, O'Bruba J, Weiss G. J. Neurotrauma 2012; 29(10): 1970-1981.

Affiliation

Advanced Technology & Research Corp., Columbia, Maryland, United States; jgoeller@atrcorp.com.

Copyright

(Copyright © 2012, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2011.2224

PMID

22489674

Abstract

Cavitation was investigated as a possible damage mechanism for war-related Traumatic Brain Injury (TBI) from an Improvised Explosive Device (IED) blast. When a frontal blast wave encounters the head, a shock wave is transmitted through the skull, cerebrospinal fluid (CSF) and tissue causing negative pressure at the contrecoup that may result in cavitation. Numerical simulations and shock tube experiments were conducted to determine the possibility of cranial cavitation from realistic IED non-impact blast loading. Simplified surrogate models of the head consisted of a transparent polycarbonate ellipsoid. The first series of tests in the 18 inch diameter shock tube were conducted on an ellipsoid filled with degassed water to simulate CSF and tissue. In the second series, Sylgard gel was used to simulate the tissue and was surrounded by a layer of degassed water to simulate the CSF. Simulated blast overpressure in the shock tube tests ranged from a nominal 10 to 25 psig (69-170 kPa). Pressure in the simulated CSF was determined by Kulite thin line pressure sensors at the coup, center and contrecoup positions. Through video taken at 10,000 frames/sec, we verified the presence of cavitation bubbles at the contrecoup in both ellipsoid models. In all tests, cavitation at the contrecoup was observed to coincide temporally with periods of negative pressure. Collapse of the cavitation bubbles caused by the surrounding pressure and elastic rebound of the skull resulted in significant pressure spikes in the simulated CSF. Numerical simulations using the DYSMAS hydrocode to predict onset of cavitation and pressure spikes during cavity collapse were in good agreement with tests. The numerical simulations and experiments indicate that skull deformation is a significant factor causing cavitation. These results suggest that cavitation may be a damage mechanism contributing to TBI that requires future study.

Language: en