Fatigue crack propagation (FCP) is the most threatening failure to welded joints due to high local stress concentration and the effect of welding residual stress (WRS). Therefore, fatigue life assessment of welded joints considering residual stress distribution is an important procedure in designing and maintaining of welded structures. In this study, fatigue life of welded structures is evaluated using the fracture mechanics approach. The WRS is predicted by using the thermal elastic–plastic-finite element analysis (TEP-FEA). Stress intensity factors (SIFs) of surface-cracked welded joints under constant amplitude (CA) loadings are evaluated using the numerical Influence Function Method (IFM). The effects of WRS on the behavior of SIFs are discussed. Fatigue life estimations are calculated for CA loadings with different stress ranges using Paris-Elber law. Calculated fatigue life considering WRS is compared with those ignored WRS. The results show that the fatigue life of welded structure decreases significantly when the WRS is considered in the calculated SIFs. This study demonstrates the applicability of IFM-based SIF calculation system to the fatigue life estimation considering WRS. The proposed approach provides accurate solutions and an efficient calculation system for fatigue analysis under different loading conditions.

由于局部应力集中和焊接残余应力 (WRS) 的影响，疲劳裂纹扩展 (FCP) 是对焊接接头最具威胁的故障。因此，考虑残余应力分布的焊接接头疲劳寿命评估是焊接结构设计和维修中的一个重要步骤。在这项研究中，焊接结构的疲劳寿命使用断裂力学方法进行评估。WRS 是通过使用热弹塑性有限元分析 (TEP-FEA) 来预测的。使用数值影响函数方法 (IFM) 评估恒幅 (CA) 载荷下表面裂纹焊接接头的应力强度因子 (SIF)。讨论了 WRS 对 SIF 行为的影响。使用巴黎-埃尔伯定律计算具有不同应力范围的 CA 载荷的疲劳寿命估计值。将考虑 WRS 的计算疲劳寿命与忽略的 WRS 进行比较。结果表明，在计算的 SIF 中考虑 WRS 时，焊接结构的疲劳寿命显着降低。本研究证明了基于 IFM 的 SIF 计算系统在考虑 WRS 的疲劳寿命估计中的适用性。所提出的方法为不同载荷条件下的疲劳分析提供了准确的解决方案和有效的计算系统。本研究证明了基于 IFM 的 SIF 计算系统在考虑 WRS 的疲劳寿命估计中的适用性。所提出的方法为不同载荷条件下的疲劳分析提供了准确的解决方案和有效的计算系统。本研究证明了基于 IFM 的 SIF 计算系统在考虑 WRS 的疲劳寿命估计中的适用性。所提出的方法为不同载荷条件下的疲劳分析提供了准确的解决方案和有效的计算系统。