Development of a Reverse Engineered, Parameterized, and Structurally Validated Computational Model to Identify Design Parameters that Influence American Football Faceguard Performance

Traumatic brain injury (TBI) continues to have the greatest incidence among athletes participating in American football. The headgear design research community has focused on developing accurate computational and experimental analysis techniques to better assess the ability of headgear technology to attenuate impacts and protect athletes from TBI. Despite efforts to innovate the headgear system, minimal progress has been made to innovate the faceguard. Although the faceguard is not the primary component of the headgear system that contributes to impact attenuation, faceguard performance metrics, such as weight, structural stiffness, and visual field occlusions, have been linked to athlete safety. To improve upon the understanding of the discrepancies in faceguard performance metrics, this research developed reverse engineered, structurally validated, and parameterized finite element (FE) simulations of common American football faceguards. The reverse engineered, FE simulation validation, and parametric analysis process was repeated for a total of nine common American football faceguards spanning four style categories, four helmet-compatible series, and three equipment manufacturers. The results comparing the faceguard models indicated measured responses—mass and stiffness—varied across faceguard styles and helmet-compatible series. Additionally, this work developed the Central Visual Field – Occlusion (CVF-O) metric and the Peripheral Visual Field – Occlusion (PVF-O) metric which quantified the amount of occlusion from each faceguard in each of the hypothesized segments of the visual field. The comparison of the nine faceguards modeled indicated a large difference in faceguard styles and helmet-compatible series; however, the results were not correlated to faceguard style, mass, or structural stiffness. Leveraging the results from the parametric analysis, an “overbuilt” faceguard was reverse engineered and modeled. The metal wire cross-sections were parameterized as an ellipse, and the mass of the overbuilt faceguard was minimized subject to stress and stiffness constraints. When comparing the models of the original manufacturer’s designs with two materials, the masses and structural stiffnesses were directly proportional to the densities and elastic moduli of the two materials. Both innovating the metal wire cross section and changing material properties have demonstrated the potential to improve upon faceguard performance metrics