Is 2D numerical modelling of welding process able to capture the residual notch stress intensity factor values?

Because of its local nature, the influence of residual stresses on fatigue life of welded joints in the high cycle regime can be quantified by the residual notch stress intensity factor (R-NSIF). The standard methodology used for its assessment requires a very fine mesh and this is the reason why 2D numerical models were used first in literature. The calculation of R-NSIF values via 3D models is very recent. It was found possible thanks to rapid numerical techiques such as the peak stress method. This approach was proven to work well but R-NSIF values coming from 3D models were not consistent with those obtained through 2D models. This work is aimed at solving that apparent discrepancy. 2D and 3D welding process numerical simulations applied to a carbon steel were carried out taking into account effects of metallurgical transformations and by varying the main geometrical parameters of the plates. It was found that 2D models are able to capture the R-NSIF value that is observed in the stationary residual stress distribution of the corresponding 3D models.