Study On The CAE Analysis And Process Optimization Of Welding Deformation Of Auto Body Sheet Metals

With the development of automobile industry and the improvement of living standards, the manufacturing and consuming mode have changed dramatically. The auto body is one of the four car assemblies. The manufacturing of the auto body not only influences the total cost but also decides the quality and taste o f a car. Welding is the most widely used connection method in modern vehicle manufacturing applications. Welding process involves electromagnetic, thermal and mechanical. The uneven heating of the welding process can inevitably lead to the deformation. Welding deformation directly affects the accuracy of the assembly of the body and increases the workload of the late correction and the auto body development costs. Therefore, it is of great significance to research the law of welding deformation and its optimization method, in order to improve the quality of productions.The paper firstly introduces the research status of numerical simulation of welding. The Resistance Spot Welding(RSW) processes of sheets with equal and unequal thickness are analyzed respectively. As a result, the distribution of temperature field, residual stress and welding deformation around the welding spot is obtained. Besides, the effects of electrode force, current time and welding current to the welding residual stress and the weldin g deformation are studied. It provides a reference for selecting the appropriate welding process parameters in the actual production.Based on linear elastic volume shrinkage method, the RSW process of wheel cover assembly is simulated and the welding defo rmation is worked out successfully. The results show that the welding deformation is so large that it exceeds the acceptable range. Considering various factors influencing welding deformation, changing welding sequence is chosen to optimize the welding deformation of wheel cover assembly and achieves the purpose of reducing welding deformation. In order to further improve the welding precision of the wheel cover assembly, the orthogonal test with the number of welding spot as factors and the welding deforma tion as test indicators is designed.The welding deformation caused by welding seam is discussed at last. The bumper beam assembly is taken as an example, and the influence of the welding sequence and welding direction on the welding deformation is analyze d. The bumper beam assembly has two levels of welding. Therefore, the impacts of the welding sequence and welding direction on welding deformation in the first welding stage and the second stage are discussed respectively. Consequently, two sets of optimum welding portfolio are acquired. When two sets of optimum welding portfolio are applied to the welding process of the bumper beam assembly at the same time, the welding deformation decreases obviously. The study provides certain theoretical basis for practical production.