Effects of Attached Body on Biomechanical Response of the Helmeted Human Head Under Blast

The results of a computational study on the effect of the body on biomechanical responses of a helmeted human head under various blast load orientations are presented in this work. The focus of the work is to study the effects of the human head model boundary conditions on mechanical responses of the head such as variations of intracranial pressure (ICP). In this work, finite element models of the helmet, padding system, and head components are used for a dynamic nonlinear analysis. Appropriate contacts and conditions are applied between different components of the head, pads and helmet. Blast is modeled in a free space. Two different blast wave orientations with respect to head position are set, so that, blast waves tackle the front and back of the head. Standard trinitrotoluene is selected as the high explosive (HE) material. The standoff distance in all cases is one meter from the explosion site and the mass of HE is 200 grams. To study the effect of the body, three different boundary conditions are considered; the head-neck model is free; the base of the neck is completely fixed; and the head-neck model is attached to the body. Comparing the results shows that the level of ICP and shear stress on the brain are similar during the first five milliseconds after the head is hit by the blast waves. It explains the fact that the rest of the body does not have any contribution to the response of the head during the first 5 milliseconds. However, the conclusion is just reasonable for the presented blast situations and different blast wave incidents as well as more directions must be considered.