Modeling Of Fem And Analysis For Body In-White Of Light Bus

The effect of car is more and more important to modern life. The development of science and technology can be seen from manufacturing of vehicle. The degree of popularization of vehicle has been very high in some developed country. Car body is one of the three assembly of vehicle. It should be finery , wide enough , clipper-built, and the excellent capability is more important. So the improvement of vehicle structure design is very important.This thesis is originated from project "Dynamic Optimal Design and System of New Numerical Car Body A40 Nanjing Iveco", which is the ten five-year industry item of the tackling key problem of Jiangsu province. In this paper, the finite element model of body in-white is completed. test and analysis of the static and dynamic properties, sensitivity analysis, and optimization of assembly are completed too. The main contents in this paper include:Build the dynamic model of an body in-whiteThe three dimension CAD model of the body in-white is created based on connection property between assembly and part.Based on the CAD model, the particular finite element model of parts are created in ANSYS by modifying of the curve and surface and predigestion of structure.Based on model test of the assembly and part, the precision of the three methods are compared. Simulated the spot welding structure by monolayer board, the screw joint structure by node coupling. Created the particular finite element model of assemblys and particular finite element model of body in-white which is made of 875 components in which the element are a type of quadrilateral element SHELL63 mainly. The degree of element quantity is above one hundred thousands which keep ahead natively. Model test and comparing of modeling method of the assembly and partDesign the modal test of the footplate assembly and part. The mass and modal characteristics are got through the test. Compared results of test and answer in harmony in computer. These dates have really revealed the accurate method for simulation in great finite element model when spot welding is dense.Analysis of the body in-white structureSome working conditions of body in-white such as bending and torsion of static analysis in computer are simulated in this paper. The characteristics of stress and deformation of body are got. These dates accorded with the statistical result of examination.The model analysis of body in-white are made in ANSYS. By the results of modal analysis of the body in-white, the body's natural dynamic features are got in the paper, and located some weakness of the structure. It has positive impacts on the improvement of bus body design.Through the contrast of effect to body sideward stiffness in three ways. Simulated rigid way with coupling five degree of freedom of node, the flexible way with Spring-Damper element COMBIN14. The characteristics of stress and deformation of body are got when sideward acceleration is supported in three ways. The sensitivity analysis and optimization of assemblyThe paper also narrated the principle and ways of bus body structural optimization. By gradient tools, it fond some design variables that affect the total weight of structure more than that of others and arranged the order of these variables according to the effects in state conditions, which pointed out the correct direction for bus body design optimization.