Analysis of the Potential of Different Foam Materials in Face Protection to Reduce the Risk of Concussions in Ice Hockey

Abstract:  Ice hockey players are at a high risk to sustain a concussion. Most of the concussion-inducing hits are to the jaw region, nevertheless, most players do not wear any protective gear shielding the jaw.  This parametric study used finite element simulations in LS-Dyna to evaluate the potential of foam materials in a jaw guard that could be attached to a helmet to reduce the concussion risk.  Here, it was investigated how nine different foam materials influence the ability of the jawguard to protect against concussion. Furthermore, aspects like foam thickness, shell thickness, and the impacting object were evaluated. In a second part, the formerly used HIII head model was exchanged with the KTH HBM, a FE model with a detailed representation of a jaw, and it was looked at how a movable jaw affects the head kinematics. Stiffer foams with a certain stress-strain behavior tend to aid best in energy absorption in the simulated crash scenarios and therefore lower the risk of sustaining a concussion. Impact angle and location influence the result significantly. Two simulated impacts show a decrease in concussion risk by up to 8.2\% and 6.9\% respectively when the jawguard was implemented, while the two other impacts resulted in an increase in concussion risk. Shell and foam thickness variation results depend mostly on the impact scenarios. However, it was found that a soft impactor helps tremendously in avoiding concussions. The hits on the KTH HBM tend to produce higher linear and angular accelerations but no significant difference is seen in angular velocity.  In conclusion, using stiff foams in ice hockey jawguards is a promising approach to attenuate impact energy caused by a collision during an ice hockey game. However, the effect of the jawguard on the concussion risk is very sensitive to the impact location and direction.