The Torsion Stiffness Analysis And Optimization Research Of Car Body-in-white

The structure analysis of car body based on the FEM is the fundamental approach in the process of car body design-oriented. Also, the whole process of car body design becomes parallel in design and analysis. New characteristics and trends of car structure design come into being from modern analysis of car body structure. And they are significant in the design process.The phase of body-in-white concept design is important to assure performance in body-in-white structure design, of which the bugs are too difficult to be corrected in subsequent design. Consequently, during the design process, Computer Aided Engineering (CAE) is applied to analyze and evaluate the characteristics in real time, which makes the design more efficiency, more systematic and more standard.Based on the investigation of the related domestic and overseas research in this field, the finite element model of a car body-in-white is established, static stiffness were carried on. Then the torsion stiffness and modal of car body structure are analyzed. Accordingly the static stiffness testing had been finished. Results comparison between the testing and analysis revealed the structural capabilities and verified the finite model's correctness. In the end the sensitivity and optimization are performed in the research.The task of the thesis is to research the generalized sensitivity adapted to large and complex system, such as the body-in-white. The sensitivity of car body structure to performance is calculated and the sensitive parts are obtained by comparison in detail. Then different parts contribution to car body is acquired, which provides the basis for design variables of optimization. The research in the thesis indicates that optimization variables calculated by this method can improve accuracy and efficiency of the results. So the whole design can be more efficient and practical.