Parametric Study on Fatigue Failure Modes of the Rib-Deck Weld Under Out-of-Plane Bending Loading

To clarify the factors affecting the fatigue failure mode of the rib-deck weld, the parameter λ defined by the ratio of the effective notch stress range (Δσ0) to the corresponding fatigue strength (ΔσR) is proposed to predict the failure mode. Three types of fatigue tests were reviewed to validate the proposed method. On this basis, finite element modeling and parametric analysis were conducted to investigate the effects of the loading mode, boundary condition, weld geometry and stress ratio on the potential failure mode. Finally, fatigue testing programs for generating objective failure modes were analyzed and suggested. Results show that the proposed method is feasible to predict the potential failure mode of the rib-deck weld under out-of-plane bending moment. The fatigue failure mode is considerably affected by the loading mode, boundary condition and stress ratio. In terms of the geometric parameters of the weld, only the weld leg length at deck plate (lw,d) and thickness of the deck plate (td) have a minor influence, while the other parameters possess no effect. Suggestions for the fatigue testing programs for generating the root-deck, toe-deck, root-weld and toe-rib failure modes are proposed, which is of valuable reference meaning for further experimental investigations.