Analysis And Optimization Of Static And Dynamic Characteristics Of Structure Of A Domestic Body-in-white

The paper of Analysis and Optimization of Static and Dynamic Characteristics of Structure of a Domestic Body-in-white is funded by a major science and technology project to be tackled in Chongqing (CSTC, 2007AA6009). Researches are focused on the static or dynamic characteristics and optimization design of a domestic body-in-white by using the finite element method. Main contents and results in this paper is summarized as fellow:The finite element model of a domestic body-in-white is established by the finite element software of HyperMesh, and then the free modal analysis is conducted by the equation solver,OptiStruct. The first eight steps free modal frequencies and vibration mode are obtained in this paper.Modal experiment of the body-in-white is conducted by the data acquisition system of Onosokki DS-2000, and modal parameters are identified by the ME'scope software, finally, the experimental data of frequencies and vibration mode is obtained. Comparative analysis on the results of modal experiment and the free modal analysis indicate that they are generally consistent.Some revisions to the finite element model is conducted according to the experimental data. Static characteristics including bending rigidity and torsional stiffness of the body-in-white are analyzed based on the revised model. Dynamic characteristics analysis of the body-in-white is also introduced on the basis of the free modal analysis. Local design optimization is done concerning the areas whose amplitude is lager. Analysis on the plates that affect the frontal collision performance is carried out.Light weight design is proposed according to the light weight technology principle. Making the car body quality as the optimization objective, the optimization is conducted under the situation that the natural frequency of the first step is improved and the natural frequencies of the second or third steps do not decrease compared with the current level , moreover, the bending rigidity and torsional stiffness of the body-in-white should keep at the current level and frontal collision performance should not be affected. Eventually ,after all these work, the natural frequency of the first step is improved by 12.23% and the equivalent overall volume of the body-in-white has been cut down by 9.01%, which proves that some apparent effects have been concluded through the optimization.