Finite Element Analysis of Penetrating Head Injury

The objective of this study is to biomechanical quantify the intracranial displacement and pressure distributions associated with civilian projectiles to advance clinical understanding of the pathophysiological consequences of penetrating head injuries. A finite element head model was developed in an attempt to investigate the penetrating processes and brain injury mechanisms. Two geometrical shapes of projectiles (flat and pinpoint headed) were considered for penetration. They were modeled as rigid bodies (6.5 and 9 g) impacting at an initial velocity of 300 m/s. The head was modeled as a spherical skull with left and right hemispheres. Material properties and damage criteria for the skull and brain were based on literature. The penetration process was modeled with eroding contact surface method with LS-DYNA. Elements considered damaged were removed from further computation when the stress or strain reached their thresholds. Temporal displacement and pressure distributions are described. The effects of projectile type on the wounding pattern are discussed. The entry location responded with higher magnitudes of displacement than other locations (e.g., exit, mid brain). The flat head projectile penetration resulted in higher magnitudes of pressure and displacement than the pinpoint projectile in the entire skull-brain system. The finite element analysis provides a quantitative understanding of the localized intrinsic responses secondary to projectile penetration.