Experimental Research and Parametric Study on the Fatigue Performance of Slotted Tubular Connection Based on the Effective Notch Stress Approach

The slotted circular hollow section (CHS) tube-to-plate welded joints are extensively used in steel structures to connect CHS bracings to main members. Nevertheless, brittle failure within the weld fatigue spot of this joint is still an urgent issue. In this paper, fatigue experiments in the high cycle regime were conducted on four large-scale specimens of slotted CHS tubular joints. Subsequently, 162 test data from existing literature were collected and re-analyzed with the effective notch stress approach (ENSA). Besides, a comprehensive parametric study was executed to determine the elastic notch stress concentration factor (SCF) of the joints with various weld types and geometries. The results indicate that the weld type is the most significant parameter affecting the fatigue behavior of this joint. The notch S-N curve FAT 225 for the ENSA recommended by the International Institute of Welding (IIW) is rather conservative for the fatigue assessment of this joint. Finally, optimal structural solutions to reduce the notch SCF at fatigue spot were recommended based on the parametric study.