The Clarification of Individual Injury Mechanism Difference in Pedestrian FE Model Utilizing Cadaver Scaling and Posturing Techniques

In car-pedestrian accidents, the pedestrian’s body size exerts strong influence on the degrees of the impacts by the vehicle on the lower limbs and the pelvis. Such individual difference affects the loading mechanism of the pedestrian accident and relates to the injury outcome. The ultimate goal of this research is to clarify the injury mechanisms of accidents of this sort. To fulfill this purpose, a 50th percentile finite element pedestrian model was developed and validated by Japan Automobile Research Institute (JARI) in the human finite element model development project by the Japan Automobile Manufacturers Association (JAMA). This model was employed in this study to reproduce full scale tests in which cadavers (Post Mortem Human Subjects) in standing position were struck by vehicles to investigate the body kinematics and the injuries caused by car-pedestrian impact. In addition, two kinds of individual scaled models were generated based on the 50th percentile standard model. In this process, the radiological data, as well as body external measurements of the cadaver recorded in the experiments, were utilized. The individual scaled models were applied to simulate two full scale tests in which two cadavers of different sizes were struck by a SUV type vehicle and a Small City Car type vehicle, respectively. For the purpose of comparison, the 50th percentile standard model was also applied to the car-pedestrian simulation. The body kinematics and the injury outcome of the models were analyzed and compared with the experimental results. It was found that, while all the models indicated acceptably good kinematics, only the scaled models could reproduce accurate injuries such as the knee ligament rupture found in the experiments.