A novel semi-analytical method for notch stress and fatigue strength analysis of tube-flange welded joints

Abstract

This paper presents a semi-analytic method to rapidly estimate the notch stress and fatigue strength for tube-flange welded joints. Considering the stress singularity effect at the weld toe, the parameters related to geometry and opening angle are simplified as singular intensity factors. The equivalent singular intensity factors can be fitted by the stress distribution rather than the peak stress at the corner. On this basis, the modified notch stress formulas for tube-flange welded joint (TFWJ) under pure bending or torsion load were fitted and verified. Meanwhile, the simple relationships between singular intensity factor, notch stress intensity factor, strain energy density and peak stress were further deduced, separately. The comparison results show that the fatigue assessment parameters calculated by the traditional approaches and the proposed method are in good agreement. Finally, four groups of fatigue data of TFWJs were summarized to verify the simplified assessment formulas.