Validation of a Football Helmet Finite Element Model and Quantification of Impact Energy Distribution

Head injury in contact sports can be mitigated, in part, through the enhancement of protective helmets that may be enabled by detailed finite element models. However, many contemporary helmet FE models include simplified geometry and material properties and have limited verification and validation over a representative range of impact conditions. To address these limitations, a detailed numerical model of a modern football helmet was developed, integrated with two headforms and assessed for 60 impact conditions with excellent ratings (0.79-0.93). The strain energy of the helmet components was investigated for eight impact locations and three impact speeds. In general, the helmet shell had the highest strain energy followed by the compression shocks; however, the facemask and straps had the highest strain energy for impacts involving the facemask. The component strain energy was positively correlated with the Head Injury Criterion, while the strain energy was not strongly correlated with the Brain Injury Criterion due to the dependence on rotational kinematics. This study demonstrated the applicability of a detailed football helmet finite element model to investigate a range of impact conditions and to assess energy distribution as a function of impact location and severity as a means of future helmet optimization.