Head responses subjected to frontal translational acceleration loads

It is important to understand the relationship between impact accelerations and head responses to improve the protection of head against impact loads. This study aims to parametrically investigate the effects of different frontal translational acceleration loading configurations on head responses using a finite element head model. A series of translational accelerations defined by loading curve shape, impact duration and peak magnitude is applied to a head model to simulate different head impact accidents. The effects of loading configurations on the brain tissue-level responses, including intracranial pressure (ICP), von Mises stress (σv) and maximum principal strain (εp), were studied, and the correlations between head injury criterion (HIC) and tissue-level predictors were analysed. It is found that the head responses increase with the increase of peak magnitudes and the acceleration loading curve shape has significant influences on head responses. The largest head responses were observed for the equivalent square shape (ESS) acceleration case. Both the σv and εp responses increase with the increase of impact durations; however, the impact durations do not affect the ICP responses. Based on the thresholds for tissue-level injury predictors, it is found that both ICP-induced and εp-induced head injuries may occur whereas the σv-induced head injury is less likely to occur under translational acceleration loading conditions. For translational acceleration loading, good correlation can be found between HIC and the εp responses; however, the HIC show a significant difference with the ICP responses for the head injury prediction. To improve the accuracy of head injury prediction with considering different injury mechanisms, ICP responses should be considered when HIC and εp responses are applied in head injury analyses.