Structral Analysis And Optimal Design Of Vehicle Body-in-White Based On Hardware-in-the-loop Simulation

The automobile industry has been quickly developed. In order to obtain the big market share, the automobile manufacturers must continuously renew the vehicle product to meet the needs of the users through using the modern design methods. The development cycle and the expense of a new passenger vehicle product are depended on the improvement of the vehicle body. The full-bearing car body has been widely used in modern cars, which nearly burdens all of the loads from the other parts of a car structure. The structural design of the vehicle body is according to its static and dynamic mechanical performances, such as stiffness, strength and vibration mode. The CAD/CAE method is generally used for the analysis and the design of the car body-in-white structures. The geometrical modeling is constructed using CAD. Then the stiffness, strength and modal analysis are carried on using CAE. The geometrical modeling is modified based on the results of the CAE. Finally the satisfactorily geometrical models and the automobile body structures are determined. However, the efficiency and accuracy of the design method need be improved further. Therefore, for the complete understanding of the relations between the body-in-white structure and its mechanical performance, research on good structural performance, low cost, fast automobile body design is one of important tasks.In this paper, a reference vehicle body-in-white structure is taken as the study object. An optimized design method of the body-in-white with the Hardware-in-the-loop is proposed by using the optimized theory and finite element method. Several key mechanical problems for the body-in-white are studied to improve the accuracy and efficiency of the optimized design. As a result, the quality of the product development is improved and the cost is reduced. The main research results are in the following.According to the structural feature of the car body-in-white, the feasible way for the geometrical modeling simplification, element choice, mesh division and weld point process are proposed using the UG model and the relevant sample. Thus it provides a solid foundation for analyzing the static and dynamic mechanical performance of the car body.Using the basic theory of optimization design, the optimal design goals and several variables are determined for the purpose and significance of the body-in-white optimization design. With CAE software ANSYS, a body-in-white model to optimize the design is established. According to the needs of the tests of the body-in-white stiffness, strength and vibration mode, a multifunction test-bed is established by the author. On the test-bed, the strength, stiffness and some dynamic mechanical characteristics of the body-in-white are experimentally obtained.Combined the CAE of the body with the test analyses, a body-in-white hardware-in-the-loop simulation method is proposed. And a systematic research program is designed. By using the above method as well as the finite element analysis, the hardware-in-the-loop amendment of the car body is proposed. Thus the efficiency of the amendment is evidently improved. On the ANSYS platform, the structural parameter sensitivity is analyzed for the body-in-white. The analytical result provides the basis for the selection of the hardware in-the-loop optimized design variables.By the optimization design and hardware-in-the-loop analysis, hardware-in-the-loop optimization method for the body-in-white design is established. And the hardware-in-the-loop optimization designs are performed for the differently optimum objectives of the body-in-white. The computed results show that the hardware-in-the-loop optimization design method is feasible and effective for the car body-in-white. Several improved recommendations are suggested for the specific kind of the body-in-white designs.