Simulation Study On Frontal Crash Auto Body Safety Of Mid-low Class Cars

Own-brand cars have occupied the largest share of China’s automobile market;they play an important role in revitalizing China’s automobile industry. However, themid-low class cars have taken up a large proportion in China’s own-brand cars. Whenthe cars encounter frontal crash, it is easy for the cars to cause serious harm to thepersons in the cars. According to the C-NCAP results in recent years, it shows that mostof the mid-low class cars get low star level. It is general three-star. The most star-losingtest is often the100%frontal overlap rigid barrier crash test. Therefore, the design ofthe frontal crash auto body safety of the mid-low class cars has become a great problemin the design of vehicle safety. This article uses a mid-low class car as the study object.Its frontal crash auto body safety is studied by the computer simulation methods. Themain research contents and conclusions are as follows:①The finite element model of the100%frontal overlap rigid barrier crash test isestablished. And then the computer crash simulation analysis is carried out. The weakperformance structures（bumper cross member, energy absorbing boxes and frontalrails） of the frontal crash safety are obtained. Using the G2peak value of the B pillarequivalent trapezia wave instead of the peak value of B pillar deceleration as animportant index to evaluate the frontal crash auto body safety is proposed in this article.②In order to facilitate the follow-up study and improve the simulation efficiency, astudy on simplifying the initial FE model is carried out. The simplified FE model iseffective, it can accurately reflect the detailed FE model’s frontal crash performances.And44%computing time can be saved.③Based on the simplified FE model, the study of the Frontal primary structures’parameters’ effect on the frontal crash auto body safety is carried out by simulationcombining the DOE. The study shows that: For a mid-low class car, it is difficult toradically reduce the B pillar deceleration G2peak value by increasing the stiffness andstrength of the frontal primary structures. Increasing the energy absorbing boxes’ lengthcan effectively reduce the B-pillar deceleration G2peak value to a certain extent.④On the basis of the above-mentioned law, the energy absorbing boxes’ length isincreased100mm, And then, the G2peak value is used as a optimization objective, theparameters of frontal primary structures are matched and optimized by the DOE and Rmethod. After optimizing, the B-pillar deceleration G2peak value is decreased34%, and the other evaluation indicators also have a greater decrease.⑤Through the studies of this article, for the own-brand mid-low class cars, If thestructure length addition is permitted by the shape design, increasing the energyabsorbing boxes’ length and matching the performance parameters of the frontal primarystructures can reduce the B pillar deceleration G2peak value effectively and greatly.And the level of the mid-low car frontal crash auto body safety can be improved.