Cavitation/boundary effects in a simple head impact model.

An experimental and numerical analysis of the impact response of a simple model of the human head is presented. A water-filled 14-cm diameter cylinder was struck by a 10 kg free flying mass. Rigid-body acceleration-time-history and the pressure at the fluid-cylinder interface were monitored during the impact event. Comparisons between the experimental results and the results of a computational model were made. The computational model used is a two-dimensional finite difference code simulating the physical experiment. The code incorporates a thin layer of air and the potential for vaporization along the inside of the cylinder. The study indicates that during a severe impact to the human head, the stresses generated within the brain can result in cavitation on the far side of impact followed by a sudden cavity collapse which can be quite violent. The study identifies how a skull-brain interface and cavitation can potentially affect the internal pressure response of the brain when subjected to a sudden impact.