Research On Influence Factors And Vehicle Front Structure Design For Protection On Lower Extremity Injuries In Vehicle-Pedestrian Collisions

In all types of vehicle traffic accidents, pedestrians are one of the most vulnerable road users due to short of protection measures. Car to pedestrian collision is a very complex process and there are a lot of influence factors. Statictical results show that lowerleg is one of the most frequently injured part of pedestrian in accidents, and sometimes can lead to lifelong disability which can cause enormous economic lose and society burden, so it is meaningful to do research focus on protection and influence factor of pedestrian lowerleg injury in vehicle-pedestrian collision.Firstly, a typical pedestrian accident case is reconstructed, then by comparing the pedestrian injury information, vehicle damage information which including the collision point and collision scratch marks, the final location of people and vehicle to assess the reliability and feasibility of the accident reconstruction. Aftertreatment animation have completely reproduced the whole process of pedestrian to car collision process, which can help to understand the pedestrian lower extremity injury mechnaism in pedestrian accidents and analyse pedestrian protection performance of different types vehicle front structure.The influence trait of car front structure parameters of two different type cars on lower extremity injury have been studied and discussed. Three lower extremity injury parameters in the EEVC regulations which including tibia acceleration, knee maximum shear displacement and bending angle are choosed as the response value for lower limb injury evaluation. By adopting orthogonal experimental design method to choose the value of each parameter and ANOVA method to calculate the mean value, range and draw level trend map respectively,finally the influence and importance of front structures parameter of sedan and mpv on lower extremity injuries are discussed and analysed.According to the result analysis of the orthogonal experimental design of these two cars, the lowerleg protection performance of sedan can be improved by reducing the bumper height, increasing bumper width and lowering the hood leading edge height to a certain extent, the maximum increase pedestrian lower extremity of the small sedan carsprotection. Appropriately reducing the bumper height, increasing the bumper, relative extended length and lowering the hood lesding height can increase the pedestrian lowerleg protection performance of mpv. Presently pedestrian regulations and the New Car Assessment Program (NCAP) have adopted the sub-components impact crash tests to evaluate the safety performance of vehicles, in that case the biofidelity of impactor will have a direct influence on vehicle safety evaluation test results, thereby affecting vehicle safety research and development, so it is of great significance to do some research about comparing and improving the biofidelity of the various types of impactor, which can improve the vehicle safety performance indirectly. For improving vehicles Pedestrian lowerleg protection performance, the current paper have compared the two lowerleg impactors biofidelity of TRL and LSTC company respectively by simulation test, then comprehensively analysied the characteristics of several other impactor and point out the main problems of the current lowerleg impactor. All these research have certain basic guiding effect for the development of higher biofidelity legform impactor.