Fracture Behavior of Load-carrying Fillet Welded Joints Subjected to Tensile Loads

For load-carrying fillet welded joints, the fracture due to the crack propagation near the root takes place frequently in practical engineering. Given the essential role of welded joints in Tee configurations with double-sided and single-sided welds, the assessments of the fracture behavior of such joints and the stress intensity factors (SIFs) related to the crack opening (mode-I) fracture and the sliding or shear (mode-II) fracture are the main topic of this study. A planar structure finite element model incorporating the crack body with the singularity in front of the crack tip is developed to simulate the failure at weld root due to the presence of non-penetrating regions. Effects of the fillet angle (theta(f)), the effective weld throat thickness (h(e)), the thicknesses of the main plate (t(p)) and the cross plate (t(c)) on SIFs are analyzed. The results show that the effect of h(e)/t(p) has a significant effect on SIFs and becomes more obvious as the crack is propagated at the weld root and inside the fillet weld. The increase of theta(f) significantly amplifies the SIFs especially for the fracture mode related to K-II. The effect of t(c)/t(p) is insignificant for the fracture mode related to K-I while its amplification results in a moderate increase of K-II especially for the single-sided fillet welds.

Automated summary

This study assesses the fracture behavior of load-carrying fillet welded joints in Tee configurations, focusing on stress intensity factors related to crack opening and sliding/shear fractures. It is found that fillet angle and plate thickness have significant effects on SIFs, especially as the crack propagates at the weld root and inside the fillet weld.