Incomplete-type welding imperfection on fatigue assessment of tubular T-joints

Abstract

T-joints are structural parts of tubular steel skeletal structural systems. The connection of these joints is assembled by seam-welding. The fatigue strength of the seam-welded T-joint is one of the most determinative factors for sustainable performance. Manufacturing-related incomplete-type welding imperfections affect this strength parameter. In this study, the influence of incomplete-type welding imperfection on the fatigue life of tubular T-joint is investigated for the different loading conditions with the equivalent structural stress-based approach. A total of 7 numerical models are established, including a reference model of a tubular T-joint and its variants with incomplete welding imperfections in the crown and saddle regions. Each numerical model is subjected to 14 static analyses including combinations of axial tension, in-plane bending, and out-of-plane bending loads. The results are evaluated in terms of fatigue life and the location of the damage. It is demonstrated that incomplete welding causes a decrease in the fatigue life and a change of location of the fatigue.