Interaction of Blast and Head Impact in the Generation of Brain Injuries

摘要

TBI occurs as a direct result of blast wave-induced changes in atmospheric pressure (primary blast injury), from objects put in motion by the blast hitting people (secondary blast injury), and by people being forcefully put in motion by the blast (tertiary blast injury) (Taber, 2006). The brain is clearly vulnerable to both secondary and tertiary blast injury. The most common types of TBI are diffused axonal injury, contusion, and subdural hemorrhage. In this report, efforts have been made to quantitatively study the effects of blast overpressure and blast-related impact on secondary and tertiary TBI. A series of nonlinear dynamic finite-element analyses have been performed on a human-head (H-head) finite-element model developed by ESI Group and a finite- element Hybrid-III dummy model by LSTC. Finite-element calculations were performed to validate the ESI H-head model against the 3D brain motion data of Hardy et al. (2001) and the intracranial pressure data of Nahum et al. (1977). Additionally, available blast loading approaches were discussed, specifically the smoothed particle hydrodynamics (SPH) method. Parametric simulations involving primary, secondary, and tertiary blast injury were performed to evaluate the effect of standoff distance, impulse and fragment speed on the extent of damage to the brain, using cumulative strain damage measure as the injury metric.