Prediction of Welding Deformation of Underframe

摘要

An inherent strain method was applied to the welding deformation analysis of left girder of GM's Buick's chassis underframe assembly. Three models are used in the calculation. Model 1 takes into account the longitudinal and transverse inherent strains; model 2 considers only longitudinal inherent strain; model 3 also takes into account the longitudinal and transverse inherent strains, but inherent strains are taken according to the function instead of the constant, for simulating the variation of the girder's stiffness during welding process. The result shows the deformation of model 2 is less than that of the model 1, the error is less than 10% of the absolute displacement. So the longitudinal inherent strain is the main factor determining boxes-girder's welding deformation. The deformation of model 3 is also less than that of the model 1, because the inherent strains of the model 3 are less than that of the model 1. At last, the welding deformation of the whole underframe was analyzed. The analysis results can be taken as references not only for the choices of welding sequence, welding parameters and fixture's location, but also for welding deformation prediction of other car chassis.