Fit effect of motorcycle helmet - A finite element modeling

Optimized assessment of the adequacy of fit conditions between a motorcycle helmet and head size in relation to prevention of head injury remains uncl ear and is complicated by wide variations in the size and shape characteris tics of helmet and wearer's heads. A finite element model (LS-DYNA3D) based on realistic geometric features of a motorcycle helmet was established to simulate the standard shock absorption test for evaluating the dynamic resp onse and fit effects of a helmet. The model was used to simulate crown, rea r and side sites impacts of the helmet. The peak acceleration and Head Inju ry Criterion (HIC) were employed to assess the protective performance of th e helmet against head injuries. The results show that this helmet model had various dynamic responses at different impact sites due to its geometric s hape, but that the impact-absorbing capability did not vary markedly within these sites. The fit conditions between the headform and the helmet dramat ically affected the assessment of the impact-absorbing capability of the he lmet in the standard shock absorption test. However, for a motorcyclist, th e helmet fit would have only minor influence on the protection against head injuries. This observation suggests that a better fitting helmet with stab le fixation should provide more protection against head injury.