Implicit Parameterized Model And Its Application On Autobody Structure Lightweighting Design

China’s auto production in2013over20million cars, car ownership has nearly137million vehicles. The automotive industry has become the pillar industry of the Chineseeconomy. In201360%of China’s domestic oil is used for the consumption of the car, whilemore than50percent of China’s oil needs are imported from other countries, this trend isalso growing. With the increase of domestic automobile production and ownership annually,automotive issues have been brought to stand out, which has three problems becomeincreasingly serious problem is the car fuel consumption, safety and environmental issues.Governments have taken appropriate measures to address these three issues includinglegislation and regulations, such as restrictions on fuel consumption regulations, safetyregulations and restrictions on emissions regulations. The automotive industry of countriesstudy that effective means and methods to solve these three problems is lightweight vehicles.Combined with the national "Twelfth Five" science and technology support program"super high strength steel hot stamping technology development and in the target models andintegrated application of" sub topic--body structure parameters of light weight designmethods and application research. In this paper, the use of implicit parametric designsoftware SFE-CONCEPT to establish the implicit parametric model of body in whitestructure according to the finite element model is verified through the target model, theparametric model of stiffness, modal properties, to determine the accuracy of the parametricmodel is established, then the weight optimization design of multidiscipline of BIWparametric model, finally achieved good reduction effect.In the lightweight design stage, the parameterized BIW is divided into the roofassembly, lateral assembly, engine assembly, floor assembly, and according to thecharacteristics of each assembly and engineering experience, selection of design variablesfrom the variables, including the thickness, shape variables, position variables, variable crosssection etc. The design variables and the performance of selected correlation calculation andanalysis of the results, analysis and selection of design variables was first elected, obtained30important design variables, which contains24thickness design variables,6shape,position, section design variables, and then optimize the design of the30design variablesselection out of the. Multidisciplinary optimization, on body quality minimum as the objective function, thewhite body bending, torsion stiffness and bending, the first torsion frequency as constraints.First, the experimental design method by the simulation of sample points, then establish theapproximate model according to the sample points, and the approximation accuracy isverified, then selects the optimization based approximation to model, the global optimalapproximation solution is obtained. At the end of the body in white structure optimizedbending stiffness, torsion stiffness, modal frequency performance verification, testing thefeasibility of light weight scheme. White body weight optimized for298.6kg, compared withthe reduction of314.3kg, weight15.7kg, reduced by5%, other properties including stiffness,modal reduction less than3%, to meet the performance requirements.