Mathematical Model for Closed Head Impact

By use of the finite element displacement formulation, the human head is modeled as a viscoelastic core bonded to a thin viscoelastic shell, which simulates the brain and the skull, respectively. For purpose of comparison, two configurations--a sperical shape and a prolate ellipsoid--have been used to describe the geometry of the human head. By applying an impact load over a small area of the shell, the head injury mechanisms--such as cavitation, caused by excessive tensile stress, and rotation, produced by large shear strain--along with their possible damage locations, are simulated. The equations of motion for the problem are in the form of second-order matrix differential equations. Solutions are obtained through the matrix iterative method.