Numerical and experimental investigations on the welding residual stresses and distortions of the short fillet welds in high strength steel plates

The current study investigates the influence of different welding sequences and external constraints on development of welding- induced angular distortion and residual stresses in the short fillet welds made of the high strength steel (HSS), S700, using the finite element (FE) method. Three-dimensional thermo-elastic-plastic FE modeling was performed in the ABAQUS FE software based on the double-ellipsoidal heat source model, temperature-dependent material properties, and considering geometrical non-linearity. The accuracy of the FE models were verified by comparing the simulation results and experimentally measured data. Both the numerical method and measurements show that external constraint has relatively larger influence than welding sequence on the development of angular distortion and the peak magnitude of residual stresses. To determine the significance of short fillet welds in terms of induced distortion and residual stress fields, the results captured by simulation and validated by measurements were compared to those of continuous fillet welds. From a numerical point of view, the results of this study are meaningful to understand the reasonable accuracy required to capture the necessary details of the welding process. From an engineering prospect, the results of this study can be important as they indicate that transverse residual stress fields due to short fillet welds are localized with considerably larger peak magnitudes compared to continuous fillet welds. With respect to the angular distortion, the results of this study show that stiffness of external constraint has a greater impact on prevention of angular distortion in continuous fillet welds than in short fillet welds. In the case of fillet welds with small lengths, beside proper clamping, other deformation control techniques such as pre-alignment of the welded members need to be considered.