Research On Vehicle Bonnet Improvement Based On The Pedestrian-Protection

With the increasing number of vehicle in China, the probability of crash accident occurring between pedestrian and vehicle has increased significantly. Due to lack of necessary protection, pedestrians are vulnerable. In all kinds of pedestrian injury, the upper leg injury accounts for a large proportion. It has been shown by a lot of studies that the bonnet of vehicle is one of the central causes of pedestrian upper leg injury. It has great significance to reduce the pedestrian upper leg injury by improving the bonnet protection capability. The study has been conducted as follows:Firstly, according to the regulation of EEVC subsystem experiment, the finite element models of pedestrian upper leg and the bonnet have been established. The accuracy of the pedestrian upper legform has been verified according to the pedestrian protection regulations proposed by the European Union. It has been showed that the finite element models of the upper legform and the bonnet have met the requirement of the regulations and can be used in later simulation.Secondly, optimization analyses on parameters such as inner bonnet thickness, outer bonnet thickness, inclination angle, crash location and material have been conducted with optimization analysis module of HyperStudy. The influences of each parameter on pedestrian upper leg injury have been acquired by analyzing the variation regularity of the parameters.Thirdly, the parameters such as inner bonnet thickness, outer bonnet thickness, inclination angle and the yield strength of the material have been selected as the objects of the study, and the parameters have been assembled by full factorial design of experiment. The results of the experiment have been analyzed by range method, the main effects of each parameter on pedestrian upper leg and the interaction effects of all the parameters have been acquired.Finally, approximate mathematical models of pedestrian upper leg and bonnet have been established by polynomial response surface method, moving least squares method and Kriging method. Fitting accuracy of the models has been analyzed, and optimization computation of the Kriging model which has the highest fitting accuracy has been carried out. Comparison and analysis have been conducted on pre-optimized and optimized model, and it is shown that the pedestrian protection capability of the bonnet has been increased by the optimization.