Research On Structure Optimize Of Coach Car-body Based On Sensitivity Analysis

Making use of computer to analysis bus structure is an important and indispensable process through the car design.The whole bus static structure finite analysis,dynamics analysis, collision finite analysis and NVH analysis become an important methods used in every automobile corporation to improve quality, shorten research period and reduce research expense.Used sensitivity analysis during passenger car structure optimization design to find parameter of girder which is sensitivity to mass change, and count optimization value of these parameter though zero rank optimization method, and adjust these optimization value according to steel measure standard. This method may improve optimization design efficiency and reduce blindness during passenger car design.This text is about one 9 meter full-loading bus, making use of the modern passenger car design method to establish finite element model of the bus frame that some car manufacturing company develop. While establishing model melt into the parameter and modularize idea to reduce preceding disposal time. Regard whole bus weight as the target function of optimization design. Biggest displacement biggest stress and the displacement and stress of danger section should being used as state variable of optimization design. Regard section dimension of each beam as design variable to calculate the whole bus model. by used step optimization method.Original models had been tested in the four conditions, analyzing the static performance, compared with the experimental data to test the model's credibility. Improved models also carried out four simulation conditions to compare with the original models' strength, stiffness differences in order to test its static performance. And improved models had been analysed with modal analysis to determine the initial dynamic performance. It was informed that the improvement of the effect is very marked through comparing the stress distribution and stiffness of the improved models and the original ones. Meeting the strength and stiffness at the premise, vehicle weight 324kg, has been recognized by the factory. It also provides a new way of optimization design for passenger cars.This optimization method is very significance to economize steel, reduce cost, improve automobile dynamical capability, reduce fuel consume and tyre abrasion or reduce circumstance pollution.