A SEMIEMPIRICAL MODEL FOR TRANSVERSE WELD DEFLECTIONS OF SQUARE TUBULAR AUTOMOTIVE BEAMS

The fabrication process for automobile frames requires tolerances in l ocating attachment points. One joining process that can affect the loc ation of reference points is arc welding. Thus, it is important to und erstand the relation between the geometry of the frame, the welding pa rameters and the deflections introduced by welding. Automobile frame m embers and joint configurations have complex geometries and contain nu merous welds. The ultimate objective of studies such as this one is to develop guidelines and simple analytical models that can be used for controlling weld deflections in complex frames. This paper describes a combined experimental and analytical approach to developing a model f or predicting and better understanding weld deflections resulting from gas metal arc welding (GMAW) on simple tubular beam geometries. A sem i-empirical model is developed based on a combination of assumed physi cal behavior and data. The model has two empirical parameters which ar e evaluated from data. This two parameter model was able to predict de flections for 45 welding experiments using a variety of beam sizes, we ld lengths and weld heat inputs with the majority of predictions being within +/-5% of the measured values. All but four predictions were wi thin +/-10%. Having established the accuracy of the model, it was then used to examine the effects of variables such as weld length, heat in put, beam height, beam size, and wall thickness on weld deflections. R esults are presented in graphical form to show trends.