THICKNESS EFFECT ON FATIGUE STRENGTH OF OUT-OF-PLANE WELDED GUSSET JOINT

The effect of plate thickness on fatigue strength of the out-of-plane welded gusset joints was investigated through out-of-plane bending fatigue test and 3-D finite element analysis for the joint specimens made of JIS SM570 high strength steel plates of 25mm and 75mm thicknesses. The specimen with the thickness of 75mm has such a lower fatigue limit as about one-half or one-third of that of 25mm thick joint under out-of-plane bendeing, because of its very high stress concentration at the fillet weld toe. Finally, the authors proposed the correction factor for fatigue strength of the out-of-plane welded gusset joint taking account of thickness effect under both of out-of-plane bending and tensile loading.