Citation

Lazarjan MS, Geoghegan PH, Jermy MC, Taylor M. Forensic Sci. Int. 2014; 239C: 73-78.

Affiliation

Christchurch Science Centre, Institute of Environmental Science and Research, 27 Creyke Road, Ilam, Christchurch 8041, New Zealand.

Copyright

(Copyright © 2014, Elsevier Publishing)

DOI

10.1016/j.forsciint.2014.03.022

PMID

24747670

Abstract

The mechanical properties of the human brain at high strain rate were investigated to analyse the mechanisms that cause backspatter when a cranial gunshot wound occurs. Different concentrations of gelatine and a new material (M1) developed in this work were tested and compared to bovine brain samples. Kinetic energy absorption and expansion rate of the samples caused by the impact of a bullet from.22 air rifle (AR) (average velocity (uav) of 290m/s) and.22 long rifle (LR) (average velocity (uav) of 330m/s) were analysed using a high speed camera (24,000fps). The AR projectile had, in the region of interest, an average kinetic energy (Ek) of 42±1.3J. On average, the bovine brain absorbed 50±5% of Ek, and the simulants 46-58±5%. The Ek of the.22 LR was 141±3.7J. The bovine brain absorbed 27% of the.22LR Ek and the simulants 15-29%. The expansion of the sample, after penetration, was measured. The bovine brain experienced significant plastic deformation whereas the gelatine solution exhibited a principally elastic response. The permanent damage patterns in the M1 material were much closer to those in brain tissue, than were the damage patterns in the gelatine. The results provide a first step to developing a realistic experimental simulant for the human brain which can produce the same blood backspatter patterns as a human brain during a cranial gunshot. These results can also be used to improve the 3D models of human heads used in car crash and blast trauma injury research.

Language: en