Development of numerical models for the investigation of motorcyclists accidents

The Finite Element (FE) method was employed to develop and enhance numerical models that can be used for simulating accidents involving motorcyclists. They are the FE models of a commercial helmet, the human head and the Hybrid III dummy. The composite shell and foam liner of the helmet, which are the most important components in terms of energy absorption, were generated using the Ls-Dyna preprocessing software. The FE model of the human head, which was developed in the Radioss environment, was converted to the Ls-Dyna format. In order to validate the head model with respect to the skull force-deflection response and intracranial pressures, two cadaveric tests reported in literature were simulated. The model of the head was coupled, through the neck, with the body of the Hybrid III dummy. This new dummy was capable of predicting the skull fracture as well as intracranial injuries such as the diffuse axonal injury. As an application of the models, the Hybrid III dummy and the new dummy were equipped with the helmet and dropped onto a flat anvil at the 7.5 m/s impact speed. The protective capability of the helmet was assessed with respect to kinematic injury predictors, such as the maximum linear acceleration of the head, and tissue level injury predictors, such as Von Mises stress in the brain.