The effective notch stress approach for evaluating the fatigue strength of rib—deck welds requires notch stress concentration factors obtained from complex finite element analysis. To improve the efficiency of the approach, the notch stress concentration factors for three typical fatigue-cracking modes (i.e., root—toe, root—deck, and toe—deck cracking modes) were thoroughly investigated in this study. First, we developed a model for investigating the effective notch stress in rib—deck welds. Then, we performed a parametric analysis to investigate the effects of multiple geometric parameters of a rib—deck weld on the notch stress concentration factors. On this basis, the multiple linear stepwise regression analysis was performed to obtain the optimal regression functions for predicting the notch stress concentration factors. Finally, we employed the proposed formulas in a case study. The notch stress concentration factors estimated from the developed formulas show agree well with the finite element analysis results. The results of the case study demonstrate the feasibility and reliability of the proposed formulas. It also shows that the fatigue design curve of FAT225 seems to be conservative for evaluating the fatigue strength of rib—deck welds.

用于评估肋-甲板焊缝疲劳强度的有效缺口应力方法需要从复杂的有限元分析中获得缺口应力集中系数。为了提高该方法的效率，本研究对三种典型的疲劳开裂模式（即根部-趾部、根部-甲板和趾部-甲板开裂模式）的缺口应力集中因素进行了深入研究。首先，我们开发了一个模型来研究肋骨甲板焊缝中的有效缺口应力。然后，我们进行了参数分析以研究肋-甲板焊缝的多个几何参数对缺口应力集中因素的影响。在此基础上，进行多元线性逐步回归分析，得到预测缺口应力集中因子的最优回归函数。最后，我们在案例研究中采用了建议的公式。从开发的公式估计的缺口应力集中系数表明与有限元分析结果非常吻合。案例研究的结果证明了所提出公式的可行性和可靠性。它还表明，FAT225 的疲劳设计曲线对于评估肋-甲板焊缝的疲劳强度似乎是保守的。