Numerical simulation on traumatic brain injury by blast waves

In military operations, industrial accidents and other explosive events, head injuries caused by blast shock waves have become one of the main injury forms of injury, but the injury mechanism and damage threshold have not been clarified yet. In this paper, numerical simulation is used to study the dynamic response process of the head under explosion load, and the effects of TNT charge, air and water media on the deformation, pressure and acceleration of the cranium and brain are analyzed. First, the air-head fluid-structure interaction model is established using Euler-Lagrangian coupling method. Based on the validation of its effectiveness, the dynamic response process of the head was analyzed in terms of pressure, acceleration and frequency of the prefrontal cranium and brain tissue. By setting the initial conditions and boundary conditions, the effects of frontal and the behind shock loadings of the blast wave on the head were simulated. It has been found that the head tissue vibrates at high frequencies, up to 7 kHz, when the blast wave strikes the head directly. The acceleration on the prefrontal cranium and brain tissue had a large value initially and become small in the late stage, while the intracranial pressure varied in a cyclical manner. In the underwater environment, there were high-frequency periodic overpressure fluctuations in the brain tissues of frontal, parietal and temporal lobes, in which peak overpressure of 3.64 MPa can be generated in the prefrontal cranium, which is well above the threshold of 235 kPa for severe brain injury. In water, brain tissue is subjected to 5 times the peak pressure, a 5 fold increase in acceleration and a 2 fold increase in frequency compared to those in air. The results of this research provide a new perspective for understanding the mechanism of damage to the human brain caused by blast shock waves, and an reference for the development of future protective measures.