Astudy On Injury Prevention Of Lower Extremities In Vehicle To Pedestrian Impact

In the accidents of vehicle to pedestrian, pedestrians become to be vulnerable due to lacking of passenger protection space, and have high frequency injuries. So the safety of pedestrians and how to reduce the injuries of vehicle to pedestrian collisions has become research issues in the road traffic safety. Because the head and lower extremities are the main injury parts, Extensive researches on head and lower extremities protection have been carried out by experts and researchers in vehicle safety both from home and abroad.Based on the vehicle-pedestrian collisions, the research on pedestrian’s lower extremities injury in this paper has been performed and the protection measures for protecting them were also discussed.Through in-depth investigations of accidents, we collected the data needed for reconstruction. Then using the software of MADYMO, we did three accident reconstructions that with lower extremities injuries. By comparing the injury parameters and the relative position between pedestrian and vehicle and the traces of collision, we obtained the consistent results between the simulation reconstructions and the real accidents.Using the software of HyperMesh and LS-DYNA, the author built a finite element model of pedestrian leg and the vehicle according to the geometry and the size of the front bumper, the hood and the front windshield structure of a sedan. Then we develop a front bumper design of pedestrian-friendly by changing the material and the structure of the cushioning foam.The study results indicate that the consistent results were obtained between the simulation reconstructions and the real accidents by comparing the injury parameters and the relative position between pedestrian and vehicle and the traces of collision and that the simulation reconstructions can effectively simulate the proceeding of the accident collision and analyze the dynamic response of the accident. It also shows that it will play an important role for collecting detailed information in the in-depth investigations of accidents to the accuracy of accident reconstruction. In the front bumper design of pedestrian-friendly, the values of the knee angle and the tibia acceleration in the original model both exceed the lower limb injury criteria in the Euro-NCAP. So we make great efforts to reduce the output values of them by changing the material and the structure of the cushioning foam. From the results it can be seen that there is some room for improvement in the knee bending angle, and the values of the knee shear displacement and tibia acceleration are far less than the lower extremity injury criteria. There could be a great improvement.This study provides an effective approach and simulation method for research on injury biomechanics and development of protection measures for pedestrian lower extremities. It also provides a feasible method for further study of the injuries of the knee and other parts in the collision of vehicle to pedestrian.