Fatigue strength evaluation of transverse fillet welded joints subjected to bending loads

Three methods of fatigue strength evaluation, i.e., the hot spot stress (HSS) method, 1 mm stress method and linear elastic fracture mechanics (LEFM) method, are used to evaluate the fatigue strength of transverse fillet welded joints in bending and the results are compared with those of fatigue experiments. It is found that the HSS is overly conservative in predicting the fatigue strength of fillet welded joints in bending. The 1 mm stress catches the geometric influence of attachments very well. A reference strength range is suggested for applying the 1 mm stress method to the fatigue strength evaluation of fillet welded joints in bending on the base of analysing available test data. LEFM is an established method for fatigue strength evaluation of welded joints and its applicability is much dependent on the ease and accuracy of quantifying the stress intensity factor (SIF) along the crack front. In this study, the SIF of fillet welded joints in bending is estimated in different ways and the resulting fatigue strengths are compared with fatigue test data.

► Three methods are used to evaluate the fatigue strength of transverse fillet welded joints in bending.
► The hot stress method fails to catch the geometric effect.
► One-millimetre stress method represents the geometric effect very well and a reference strength is suggested.
► LEFM estimations are made with SIFs obtained in different ways and useful suggestions are made.