Background: In wars, when bullets impact the bullet-proof helmet, kinetic energy will be transferred from the skull to brain tissue, resulting in the rapid deformation, stretching, shearing and final destruction of the soft tissue. In recent years, with the continuous upgrading of protective equipment, the penetration ability of bullets into protective equipment has gradually decreased, but the problem of head injuries caused by deformation of the back of the helmet has become increasingly prominent. It is of great significance and value to study the brain trauma caused by the bullet impact of the bullet-proof helmet.
Methods: First proceeded the rifle bullet impact physical brain model experiment and the results were used to verify the simulation process of high-speed bullet impact, simulated the bullet hitting brain model from different directions (front, side, rear) and different incident angles (0°, 15°, 30°), then evaluated the craniocerebral injury by analyzing skull stress, intracranial pressure, principal strain, and shear strain.
Results: When impact from the rear, the peak intracranial pressure and skull stress increase by 20%-25% compared to the front impact, and the principal strain and shear strain are 1.5-2.2 times than that of the front impact. In the same impact direction, the severity of brain injury will increase with the increase of incident angle. When the incident angle increases from 0° to 15°, the intracranial pressure and skull stress both increase, the principal strain and shear stress increase sharply with 6-7 times.
Conclusions: Under different shock conditions, the dynamic response of the brain is sensitive, and the impact position and angle of the bullet have important influences on the brain. It is more likely to be caused injury during rear impact, and as the incident angle increases, the severity of the injury will become more serious.