Ice hockey, one of the most popular sports in the world, is a contact sport that is always associated with huge risks of traumatic brain injuries (TBIs) resulting from high-velocity impacts. Although technology in player protection equipment has advanced over the years, mild traumatic brain injuries (mTBIs) like concussion remain prevalent. Finite Element (FE) analysis presents a methodology to recreate accidents in an effort to study the effects of protective helmets and predict brain injuries. This study aimed at improving the response of an existing ice hockey helmet FE model during different impact conditions and reconstructing an ice hockey collision using FE simulations. First, the shear response of the Expanded Polypropylene (EPP) material for the helmet liner was improved by means of a single element simulation to replicate the experiments. Simulations of helmet drop tests were then performed to validate the helmet FE model. Two different designs of the helmet model were implemented, one with normal properties of the foam and the other with a softer foam. Actual cases of ice hockey accidents were then reconstructed using positioning and impact velocities as input from video analysis. As player to player collisions had not been reconstructed for ice hockey using two player models, it was decided to use two full body Human Body Models (HBMs) for the reconstruction. The biomechanical injury parameters for the accident reconstruction were plotted and compared with injury thresholds for concussion. The kinematic results achieved from the drop test simulations showed a considerable decrease in peak values for resultant accelerations, resultant rotational accelerations, and resultant rotational velocities. These results also exhibited better CORrelation and Analysis (CORA) scores than previously achieved. The biomechanical analysis of the accident reconstruction showed the strains in the brain for the concussed player to be more than the threshold for concussion, which confirms the validity of the reconstruction approach. The results of this study show an improved response of the helmet FE model under different impact conditions. They also present a methodology for ice hockey accident reconstruction using two full body HBMs.

The aim of this research was to produce a reliable finite element model of a helmet, that could be used to simulate approval tests as well as impacts to investigate the safety offered. A 2D and 3D mesh was generated from the CAD file of an Easton Synergy 380 with HyperWorks, and then checked referring to standard parameter values. A few specimens cut from the liner were tested with the Instron Electropuls E3000 (Instron, High Wycombe, Great Britain) machine to determine Young’s modulus, Poisson’s ratio and the density of the EPP. The numerical model was characterised with appropriate materials with Ls-PrePost, such as ABS for the shell, EPP for the liner and steel for the impact anvil. The foam was implemented both with the *063_CRUSHABLE_FOAM and the *126_MODIFIED_HONEYCOMB card, in two different configurations. The helmet model was coupled with a finite element model of a HIII head form and three impact scenarios were set up. Backward, lateral and pitched impact were simulated and results were compared with those obtained from the experimental tests carried on at the MIPS. The two configurations were tested in all the three scenarios. The correlation between numerical and experimental results was evaluated by analysing the linear and rotational acceleration, and the rotational velocity, recorded by the accelerometer positioned inside the HIII headform. The parameters used were the Pearson correlation coefficient, the peak linear acceleration score, the shape of the curves, the time occurrence of peaks and the percentage of the difference between them. The first configuration showed good correlation scores (>85%) for the backward and lateral impact, for the rotational velocity and acceleration, while lower values were recorded for the pitched impact simulation. Lower values (70.88% and 77.76%) were obtained for the peak linear acceleration score, which stress the need for modifications of the contact definition in Ls-PrePost or a more detailed material testing. Worse results were recorded for the second configuration, but the smaller computational time required suggests that more attempts should be done in this direction.