The fatigue behavior of welded joint has local damage characteristics.Based on stress field intensity(SFI) theory
the field diameter of fillet welded joint was analyzed
and the stress field intensity at the weld toe of fillet weld joint of flange was calculated using elastic-plastic finite element method.Based on the calculation results and the results of S-Ncurve of smooth specimen of the same material
a fatigue life evaluation of flange fillet welded joint was obtained.The precision of fatigue life prediction with SFImethod is better than the one with the local stress-strain method
and the result is much closer to the experimental result.