Research On The Protection Of Pedestrian Legs During Car-pedestrian Impact And Its Assessment Method

At present, European countries and Japan have developed pedestrian model and lower legform impactor model. They have also established corresponding experimental assessment methods and standards to assess the protection performance of the car-front to the legs of pedestrian. However, some studies indicate that the lower legform impactor model can't evaluate the protection of the car-front to the legs well, and the protection performance of the car-front to the legs needs to be improvedThe purpose of this research is to improve the protection to the legs by changing the car-front structures and to develop a lower legform impactor with simple structure but good performance in assessing the protection of different car-fronts to the legs. Therefore, a lot of researches on documents were carried through, research status and methods in this field were analyzed, from the point of view of anatomical structure of lower extremity and injury biomechanics, injury type, injury mechanism and corresponding injury criterion of leg were researched.In this paper, a car-pedestrian impact model was established by using the available multi-body pedestrian model and the software of MADYMO. By changing the main structure parameters of the car-front, the influence of car-front structures to the knee injury was analyzed, and the car-front structures that cause minor injury to the legs were proposed. As this research indicates, decreasing the height of bumper and bonnet leading edge, increasing the distance between the upper and lower face of bumper and the distance between bumper lead and bonnet leading edge will decrease the injuries to the knee joints of pedestrian. The results of this research have good consistency with the results of foreign traffic accident data statistics.Assessment performance of impactor was also analyzed by using traffic accident data and mathematical models in this paper. A new legform impactor model was established based on parameter analyses of the definitions of legform impactor. By mending parameter definition of the new impactor using simulation experiments, assessment performance of the impactor was improved. In the simulation of assessing car-front of three different dates by using legform impactor, new lower legform impactor has well synthetically assessment performance, which can be used to assess the protection performance of car-front to the leg very well. So it can also be used for new car development and assessment.