Brain pressure wave propagation during baseball impact

The purpose of this study was to examine a mechanism of brain injuries during baseball impact. A baseball helmet was attached to a novel surrogate head, which simulated the intracranial structure of a human head, and baseball impact tests were carried out using a high-speed cannon system. In addition, the baseball impacts were simulated using a corresponding finite element model of the head and helmet. From the results of both the experimental and simulated impacts, the peak acceleration of the brain was greater than that of the skull, which was due to the propagation of pressure waves, in turn reflected in the intracranial space. The peak negative pressure reached the cavitation threshold on a broad area of the brain surface, repeatedly. This phenomenon was different from the brain deformation in other impact conditions such as football and traffic accident cases. Therefore, a new design philosophy for a helmet which reduces the effects of pressure wave propagation may be required to mitigate brain injuries.