Effectiveness of the football helmet assessed by finite element modeling and impact testing

Mini-sled impact tests using a Hybrid III head-neck complex with and without a helmet were conducted to contrast resulting head accelerations. Because this experimental configuration includes both the linear and rotational impacts to the head, it represents the real world football impact condition better than drop tests traditionally used to evaluate the protective effect of a helmet. It was found that wearing a helmet significantly attenuates head linear acceleration but not angular acceleration. Additionally, a 3-D finite element model of a football helmet simulating all of its essential components was developed and validated to investigate its effectiveness in energy attenuation. Results from these modeling and experimental efforts have shown that the helmet was less effective in attenuating impact energy due to an impact to the front-boss and side of the helmet. The validated helmet model can be used in conjunction with a validated human head model to design helmets intelligently by determining optimal liner thickness and stiffness for omnidirectional protection of the head, once an acceptable injury criterion is established. In addition, the helmeted head model can be used as an inexpensive adjunct for current test procedures and for the establishment of new procedures.