Abstract A strain-based fatigue reliability assessment of welded ship structural joints is presented. To obtain a complete description of the fatigue stress acting on a butt-welded joint in a ship, a probabilistic distribution for the low cycle fatigue stress range is developed considering the uncertainty in the static and dynamic stresses. A model considering the effect of a secondary notch embedded into the primary notch is developed considering the low and high cycle fatigue regimes. The misalignment, secondary notch, residual stress and fatigue limit effects are incorporated into the notch strain approach on which the fatigue reliability assessment is based in the present study. The efficient Advanced Mean Value method is used to derive the distribution of the fatigue crack initiation life where a detectable crack is formed. The influence of different modelling options is analysed, and the importance of accounting for the misalignment, residual stress and especially the proposed secondary notch effect is discussed. The sensitivity of the reliability estimates to the variables’ uncertainty is investigated based on the First Order Reliability Method, and the dominant ones are identified.

中文翻译：

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基于应变的船舶结构焊接接头疲劳可靠性评估

摘要 提出了一种基于应变的船舶焊接结构节点疲劳可靠性评估方法。为了获得作用在船舶对接焊缝上的疲劳应力的完整描述，考虑到静态和动态应力的不确定性，开发了低周疲劳应力范围的概率分布。考虑到低周和高周疲劳状态，开发了一个考虑嵌入到主槽口中的二次槽口的影响的模型。未对准、二次缺口、残余应力和疲劳极限效应都被纳入了缺口应变方法，疲劳可靠性评估基于该方法在本研究中。有效的高级平均值方法用于推导出形成可检测裂纹的疲劳裂纹萌生寿命的分布。分析了不同建模选项的影响，并讨论了考虑未对准、残余应力，尤其是建议的二次缺口效应的重要性。基于一阶可靠性方法研究了可靠性估计对变量不确定性的敏感性，并确定了主导因素。