Design And Optimization For Crashworthiness And Safety Performance Of The Side Parts Of A Passenger Car

With the increasing of the vehicles in global transportation, road traffic accidents have become a major social problem. Each year the number of death is estimated as about 1,200,000 in traffic accidents around the world. Road traffic accidents have brought a serious disaster to human life and social economy. In China, the grade crossing is the major pattern of urban traffic road. Thus, the occurrence of side impact accident is the highest in all type of accidents, and the injury rate is also the highest in all accident scenarios. The fatality rate of side impact is only less than that of front impact. So, research into occupant protection from side impact has become an important topic in the passive safety area. The regulation on the occupants'protection in side impact accidents was developed by China Automotive Technology & Research Center according to ECE R95, which has been brought into effect in July 1st 2006, and Chinese New Car Assessment Program (C-NCAP) was also issued at the same time.The aim of the present thesis is to investigate the crashworthiness of side structure and how it affects the injury of occupants. For the side door reinforce bar, the correlation of the key structural parameters with crashworthiness was analyzed by using sub-structure model in terms of different sections of the reinforce bars. Also investigate how the parameters of the inner trims affect the injury of occupants. Based on the Response Surface Method (RSM), the reinforce bar was optimized in terms of the sectional parameters and thickness. The orthogonal design method and response surface method were used in optimization for minimizing risk of occupant injury. At last, the paper provides some countermeasures to protect the occupants and discuss their validity.Firstly, the paper outlines the side impact regulations of China and basic theory of crash safety. Then a mobile deformable barrier FE model and a car FE model was established and verified the finite element models by comparing them with the test data and requirements. As a poor crashworthiness performance of the door, the side reinforce bar was optimized to improve its performance. The injury parameters of dummy were obtained and evaluated by using MADYMO software and PSM method. The correlation between the parameters of door inner panel and occupant injury criteria was analyzed in side impact through simulation. The design parameters of trim optimized to improve the crashworthiness and reduce injures of occupants.The results of this study indicate that crashworthiness performance of side bar has been greatly improved by optimization design. The value of the dummy injury parameters can be reduced by optimizing the stiffness and thickness of inner trim panels of door and B pillar. The RSM can be used in the stage of concept design of a new car. Using sub-model can save the costs of calculation and production.