Étude biomécanique de la protection de la tête au hockey

Abstract

Head protection is of major interest in contact sport such as ice hockey. In the past few years, an awareness about the damages induced by a frequent exposure to head shocks raised within the ice hockey community: players of any level, fans, leagues and equipment manufacturers. To limit the ransmission of these traumas to the brain, neurological studies have highlighted the role of the linear and the angular acceleration as being likely responsible for concussions. The engineering team of Reebok-CCM Hockey tries to optimize the design of their helmet, through the geometry and the materials, to reduce the accelerations of the head. However, it is difficult to establish a link between the design choices and the experimental results of the impact test. One of the causes of this difficulty is the lack of information about materials and poverty of the data supplied by the manufacturers. To answer these problems, the development of a parameterized FEM of a helmeted head which will be of use as support to design and evaluate new hockey helmets has been considered. This project is a feasibility study on the development of this model. Thus, the specific objectives of this preliminary project are: 1. To characterize the properties of the helmet protective foams under dynamic loading; 2. To develop and validate a parameterized finite element model of a foam layer under shear and compression loading; 3. To evaluate the behavior of a head-neck HYBRID III dummy finite element model. To meet the first objective, an experimental testing system was used to determine the stress-strain curves of seven different types of protective foams submitted to impacts. A design of experiment was realised with two foams (EPP and VN602) and six characteristic parameters have been identified to establish the foam behavior and its strain rate dependency. Besides, shear-compression combined loading tests have been realised and led to a proof of principle. The second objective led to the development of parameterized FEM of the protective foams mechanical behavior under dynamic conditions. The models were validated with respect to experimental data. Finally, the third objective was fulfilled by numerically reproducing experimental impacts to the head-neck HYBRID III dummy. A correlation exists between experimental and numerical linear and angular accelerations, which allows a relative comparison. However, the equivalence between experiments and simulations has not been fully proven and future investigations will be needed to clear up this point. In conclusion, this study allowed, on one hand, to characterize the dynamic behavior of protective foams and on the other hand, to show the feasibility to model their behavior. The evaluation of the HYBRID III FEM behavior must be pursued to give full confidence in the feasibility of developing such a parameterized FEM of a helmeted head which will be of use as support to design and evaluate new hockey helmets.

Date	16 Jun 2016
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Yvan Petit (Supervisor) & Éric Wagnac (Co-supervisor)