An accurate computation of fatigue stress requires the construction of a detailed finite element (FE) model for all fatigue critical locations, followed by FE analysis that demand intensive computational resources. Therefore, instead of using the actual hotpot stress, the common practice is to multiply the nominal stress by the corresponding stress concentration factor. This approach is again an approximation that typically introduces significant uncertainties into the direct calculation procedure. The stress concentration factor has a significant influence on the results of a fatigue analysis and must be computed in a more accurate way in which realistic load combination is considered.