A Study And Improvement On Vehicle Body Structure Safety In Front Oblique Impact

The vehicle front impact contained 100% front impact,40% offset impact and front 30°oblique impact, which are the most common types of fatal crash accidents. At present, most research works of the front impact crashworthiness are focused on 100% front impact and 40% offset impact, but not considered the front 30°oblique impact in China. However the 100% front impact and 40% offset impact can not explain all kinds of front impact types. Therefore, it is very important to pay attention to the front 30°oblique impact for the result of improving the vehicle safety.Based on the American FMVSS 208 front oblique impact statute, the car finite element model to be used in front oblique impact simulation were developed, and the validity of the finite element model was verified by using computer simulation method from front impact and offset impact validation method in this paper. Then studied the key component front side rail crash characteristics under 0°,5°,10°,15°four different angles on front oblique impact. According to the bad deformation characteristics of front side rail on the front oblique impact,improved the impact action to the front side rail from the thickness and section shade. Mending the rail from thickness and filled Al-honeycomb and calculated the simulation model.The result show filled Al-honeycomb in the front side rail can improve the deformation characteristic and energy absorbing ability about front side rail in reason.Calculated the car front 30°oblique impact finite element model, analysis was carried out with the automobile system energy and acceleration cueves. Through force transfer path and components deformation characteristic analysed the key components which are in the car foreside. From the results, we can see the car structure in the driver side is weak and fire wall intruded deformation is biggish. Integrated theory method and project experience, chose three mothed such as filled Al-honeycomb, TWBs (tailor-weld blanks) technology, parts strengthen to improve the impact ability. Learned the improved deformation characteristic about floor firewall incrusion and front side rail.On the condition, I discussed effective step to improve automobile front oblique impact.The results of research show that the most effective measures to improve the crashworthiness of mature body structure is adding strengthened components which doesn't affect the function of the location of the original parts; Comparing with the front impact, the front oblique impact increased the occupant injury risk and request to a higher crashworthiness of the car; The safety of a passenger car could be improved in front oblique impact by filling Al-honeycomb in the side rail, using TWBs thchnology and strengthen the weakness parts can improve front oblique ability effectively. The method and the results of this study provide a significant reference to improve the vehicle safety and reduce the occupant injury risk in front oblique impact.