Study Of Qualitative Simulation Model Fonudation Of Body-In-White Structure In Conceptual Design Stage

During the conceptual design stage, analyzing the structural scheme of the body-in-white, and then deciding'optimum scheme'can provide alternative schemes to the detailed design stage. Then the modification times will be less and the cost used in modifying the product will be cut down. At the same time, due to the indeterminacy and the conceptual design stage needs large number of comparison schemes, it is difficult to found lots of accurate model. Besides that, the characteristic of the body-in-white (BIW) is another factor which leads to this difficulty. During study, the qualitative simulation theory will ignore the secondary causes and the indeterminacy, thus it can be used in analyzing the BIW structure performance during the conceptual design stage, and the'optimum scheme'can be determined quickly and accurately.The mainly research contents and conclusions in this paper are as following: Firstly,simplifying the BIW structure in the conceptual design stage is the solution .This simplification is based on the same vehicle types and the pretreatments in the finite element analysis. The characteristics of the BIW are complexity, inheritance and hierarchy, and those characteristics are other bases of this simplification. Besides that, a kind of simplification principle is provided in this paper. The BIW structure will be simplified using those principles. The simplification principle is that the performance of the simplified model is consistent with the performance of the referenced models. So the simplified BIW structural performance can reflect the real performance of the BIW.Secondly, a module for special use called'Conceptual Body Design'was founded to solve it. Parametric modeling and the secondary development tools called'UG/Open'provided by UG software are the bases of the module. The function of the special use module includes creating new part, editing/modifying parameters of the part, evaluating the performance of the part. Large numbers of simplified BIW structure models can be founded rapidly using this module. The special use module meets the requirements of the BIW structural scheme in the conceptual design stage. It's convenient to modify those parametric models and making comparisons between different models is also conveniently. Those parametric models are the bases of the qualitative simulation analysis.Finally, using qualitative simulation theory to analyze those parametric models created though the module for special use called Conceptual Body Design. One kind or more'optimum schemes'of the BIW structure can be determined though this qualitative simulation analysis. And those'optimum schemes'are the alternative schemes during the detailed design stage.In a summary, during the conceptual design stage, those measurements including simplifying the BIW based on the same vehicle types, founding a specialized module to found large numbers of BIW compared models, and analyzing those models using qualitative simulation theory can meet the requirements: founding those models rapidly, modifying those models easily, analyzing those models accurately and effectively. Thus, the purposes that shorten design period and cut down cost can be achieved.