Numerical Analysis Of Dimensional Variation For Automobile Panels Welding Assembly Deformation

Automotive body is the important composing parts of an automobile, and is also the important factors of inspiriting people's purchase desire. Hence, automotive body quality control technology is the significant means that automobile manufacturer enhance competition ability and occupy market. Welding process of automobile panel is the key working procedure in the manufacturing processes of automotive body with its quality directly impact on the appearance and functionality of automobile. Because of complexity of effect factor of welding deformation, design and manufacture of automobile panel welding fixture tend to be by means of try and error method to meet requirement, which is severely restricting development cycle of automotive body.Stamping dimension variations of automobile panels, as an error source of welding assembly, have a very significant impact on the quality of automobile body welding assembly. Springback is the principal factor of producing dimensional variation of stamping forming. The reason of stamping springback is analyzed and springback mechanism and control methods are discussed in the paper.To control the deformation of a welded assembly, the resistance spot welding assembly process for automobile panels is analyzed, and then a simplified finite element analysis method, in which pre-stressing was used to reflect the workpieces'dimension variation and the node coupling method was used to express the welding spot, is proposed to simulate welding assembly process. Further, in this paper secondary development of ANSYS FEA software is carried out through stress data file, and the Monte-Carlo method is used to combine with the proposed finite element analysis method to consider the stochastic characteristics of dimension variation of workpiece. The established analysis method is applied to take examples for welding assembly in series and parallel of sheet metal and welding assembly in parallel of certain automobile's Rear Back panels.The established analysis method in the paper, which is closer to manufacturing practice, can be used to study the welding assembly deformation of automobile panels by considering the workpiece'displacement variations as random inputs, and simultaneously compute welding assembly deformation of a batch of assemblies. At the same time, by using this analysis method, through considering the effects of stochastic characteristic of displacement variations of workpiece on welding assembly deformation, the knowledge of dimension variation propagation mechanism for welding assembly deformation is deepened. And further, by analyzing sensitivity of welding assembly deformation on inputs, useful information for welding fixture optimization design can be obtained and the welded assembly variation source can be clearer.