The Crashworthiness And Structural Optimization Of A Passenger Car Under Multiple Impact Conditions

Today the development of the automobile, Has not only as a means of transport,But a symbol of modern civilization. The functions of the automobile have improvedgradually and the design is more humanized. When practicality and comfort reach ahigh level, safety, energy-saving technique, environmental protection and otheraspects more and more get people’s attention. With the change of the car’sperformance and the traffic conditions, the speed of the car is becoming more andmore high. But the probability of traffic accidents is growing. Traffic accidents notonly caused huge economic losses, but also threated the people’s life every year.So,each country, automobile enterprises and scientific research institutions have carriedout the vehicle safety research. For the Purpose of Passing the crash safety statuteand marketing, the most automobile companies must rethink the safety body invehicle design. As it is too expensive to do the crash test of the real automobile anddifficult to collect the data of the crash test，the computer simulation of the car crashis thought to the most effective method to research the automobile safety，andapproved by the most automobile companies. Based on practical engineeringbackground，the paper presents the research on the whole body of a sedan vehiclewith integrated method of computer aided finite element analysis and the crash ofthe vehicle to find out the unreasonable design，and the improvement of thecorresponding parts of the sedan-vehicle.First, the paper pointed out the import for researching impact safety,summarized FEA development course in vehicle industry, analyzing researchinglevel and tend of crash safety in China and foreign, detailed introduced the impactregulations and method in China and foreign later, analysis our country’s impact regulations require and characteristic. And then, discussed the FEA theory andelement type, essential equation for simulation, integral arithmetic etc, establishedvehicle impact FEA model. According to the country impact regulation, performeimpact simulation. Compared the analysis results with the real vehicle test, makingthe baseline for the next model modification. By analyzing effects to impact from Bpillar,closure, lower sill, seat crossbeam etc, advanced some structure optimizationproposals and performed the every case to find the best result. Finally, testing againthe real vehicle side impact and BIW stiffness to prove the FEA result’s correct. Theresults show that, we could through optimization to ensure side impact safetyrequirement and stiffness requirement when changing BIW structure and reducingmass.This paper used the automobile collision analysis software LS—DYNAT toanalyse the result of frontal crash and side crash. Concluded the collision response,displacement, velocity and acceleration of automobile collisions. Have got theevaluation of the crashworthiness.The paper acquired collision energy dissipationrelations and reliable evaluation results from collision process behavior.Deformation analysis after the collision, proposed the optimization program andsimulation comparison.Sought the crashworthiness methods to improve the bodystructure, the body structure can achieve the desired deformation under externalshocks, the amount of deformation is controlled within a certain range, To assurancethe safety space of passengers, makes the body absorb more collision energy. Makecollision energy transfer to the vehicle occupant reduce to minimum, so that theoccupant suffered the smallest acceleration.