Abstract
The purpose of this research is to examine fatigue strength of under-matched welded joints applied to load-carrying cruciform fillet welded joints made of high strength steel. First, in order to grasp influences of the magnitude of stress concentration on differences between fatigue strength of under-matched welded joints and over-matched welded joints, fatigue tests under axial loading and bending were carried out. Next, fatigue test data obtained this research were compared with results reported in previous research. Based on the comparisons, fatigue strength of under-matched welded joints is similar to that of over-matched welded joints not depending on the magnitude of stress concentration.
