The Crashworthiness Research Of Vehicle Key Structure

With the industrial foundation and economy continue increased, automobilebecoming an indispensable transportation in people’s life, along with the increase ofthe car ownership also brought frequent collision accident. Design a car withhigh-strength body, perfect passive safety as well as large passenger space in the limitof national regulations, has been an important research topic in the field ofautomotive R&D. Automobile collision is a transient process, involving nonlinear andlarge deformation, combination the numerical simulation and optimization designtheory provides a new way to research car body crashworthiness, greatly reducing thetime cost and economic costs of crashworthiness research.Most of the impact load and energy are dissipated and absorbed by the thin-wallof car body structure. This paper using the finite element software to establishedcollision model and carried out the vehicle crashworthiness research under thefollowing works:First, because almost all of the car body components are thin-walled components,when intense collision occurs, the thin-walled component occurred plasticdeformation, accompanied by this phenomenon components absorbed a lot of energy.The article first discusses the influence of various parameters for typical thin walledcolumn during the collision process, the results show that the cross-sectional shape,wall thickness, solder joint distribution ect. has a different influence ofcrashworthiness. Then the article use the taguchi design method for expansionendergonic structure research, concluded the various parameters of expansionstructure has different influence of crashworthiness.Second,in the past automotive collision simulation most ignored the residualeffect of sheet metal forming, this to a certain extent affect the simulation accuracy.Combining mapping technology, mport the residual strain, residual stress and thechange of thickness information which produced by stamp moldle to the collisionmodel, than use the ls-dyna to simulation calculation, and comparative analysis theinfluence of forming varisable to components crashworthiness, analysis showed that the different forming variables has different influence of crashworthiness.Third, the article established the vehicle collision modle and compared with realcollision experiment to test the reasonableness of modle. then select some thin walledcomponent like bumper, front longitudinal ect. which has greastest influencecrashworthiness, use the thickness of these components as design factor. Simulationexperiment was carried out by uniform design, using stepwise regression methodoverfitting the test results, get a good fitting precision function. Finally by using thegenetic algorithm to multi-objective iteration optimize the regression model, andimport the results into the vehicle model to calculate, it shows that significantlyimprove the responed of car body crashworthiness.The article research about three aspect: Explore the effects on crashworthness ofvarious parameters for thin-walled structure; Research the influence ofcrashworthness by forming variable; Using unifor design and stepwise regression tooptimize the vehicle front crashworthiness. The article not only from the theory tostudy the mechanism of crashworthiness, provide the basis for car body parts design,but also adopt the precise model and optimization theory to improve the vehiclecrashworthiness, this can accurate, economic and rapid solution the optimizationproblem of car safety, this has important reference value and significance.