Traction stress-based fatigue failure mode identification of load-carrying welded cruciform joints

This paper proposes an analytical solution of traction stress at the weld root of load-carrying welded cruciform joints, incorporating the effects of weld geometry, especially the gap between the loading and intermediate plates. Additionally, this study suggests fatigue failure criteria to differentiate toe and root failures and verifies these criteria by 372 experimental data. Results indicate that: (1) the analytical solution can quantify the stress state at the weld root and predict the root cracking angle; (2) the failure criteria are adequate to judge toe and root failures with high accuracy. Finally, weld geometry effects are discussed, and fatigue design for joints is suggested.