Research On Autobody Parametric Model Lightweighting And Lightweight Effect Evaluation Method

The lightweight of automobile is the effective way to three problems which are energysaving, environment protecting and traffic safety that need to be solved urgently for theworld automobile industry when it is developing rapidly. Lightening the weight o fautomobile not only reduces the cost of material and moving resistance and fuelconsumption of automobile, but also play an important role in improving the fuel economyand decreasing exhausts of automobile. The weight of the white car body which is the mainbearingpart of a car is40%of the whole car’s weight, so the lightweight of the BIW is veryimportant for reducing the weight of the whole car.The research is developed based on the project―research on the body parameterizedlightweight design technology and its integrated application on the target models‖which is apart of the National12th five-year Science and Technology Support Program―R&D of thekey lightweight technology and integrated application on the car‖. The parameterizationmodel of a Chinese A grade car is established and lightweight design of it is performed, inaddition, the assessment method for lightweight is researched.The parameterization model of the BIW is established based on the original FEsimulation model using SFE-CONCEPT. Both the static performance and the dynamicperformance of the car-body model are analyzed with FEM and the correctness of the FEmodel and rationality of the structural property of the BIW are verified after the comparisonbetween the calculated results and the experimental ones.The response rate to the depth of the blank from car-body mass, modality and stiffnessare analyzed respectively with the method of structural sensitivity analysis beforeoptimization which provide the basis for selecting the design variables of structural optimization and improve the optimization efficiency.28values of the blank depth are selected as design variables which are of higher masssensitivity and lower modality and stiffness sensitivity based on the sensitivity analysisresults. The optimization design of which the car-body mass is the objective function andcar-body stiffness and modality are constraints is carried out, after that, the optimized blankdepth is adjusted based on actual production. The stiffness and modality analysis isperformed after reassignment to the blank depth on the basis of adjusted depth to verify thefeasibility of lightweight techniques.At last, the content of lightweight of cars and evaluation parameter of body shelllightweight effect——lightweighting coefficient which is common in western countriescurrently are reviewed comprehensively. The evaluation index for the BIW lightweight andvehicle lightweight is explored and the conceptions of the BIW lightweight coefficient andvehicle lightweight coefficient are proposed according to the actual requirements.