The residual stress at a dented area is critical to oil and gas pipelines’ integrity and safe operation. A three-dimensional (3D) finite element-based model was developed to investigate the residual stresses in two typical dented areas during the lifecycle stages (pipeline construction and pipeline operation stages). Use of this model enables study of the distribution of the maximum residual stress (σ_RS) in the dented area. The effects of indenter size, pipeline size, internal pressure and dent depth on the residual stress of two types of dented pipelines were analyzed. A nonlinear regression analysis was used to obtain multi-factor formulas for predicting the σ_RS for different dents during different lifecycle stages. The results show that the σ_RS distribution in the dented area changes with dent depth. With σ_RS for a transversal dent being almost always greater than that for a longitudinal dent. During the pipeline construction stage, the influence of indenter size or pipeline size on σ_RS is almost the same for the two types of dent, whereas, during the pipeline operation stage, the influences are distinct. The tendency for pipeline size to affect σ_RS differs slightly as the dent depth increases. Multivariate fitting formulas can provide a reference for estimating σ_RS.

凹陷区域的残余应力对于油气管道的完整性和安全运行至关重要。建立了基于三维（3D）有限元的模型，以研究生命周期阶段（管道建设和管道运营阶段）的两个典型凹陷区域中的残余应力。该模型的使用使得最大残余应力的分布（σ的研究_RS在凹状区域）。分析了压头尺寸，管道尺寸，内部压力和凹痕深度对两种凹痕管道残余应力的影响。使用非线性回归分析以获得多因素公式用于预测σ _RS在不同的生命周期阶段不同的凹痕。结果表明，σ _RS凹陷区域的分布随凹痕深度而变化。与σ _RS为横向凹痕是几乎比总是大于一个纵向凹痕。在管道施工阶段，压头的尺寸或管道尺寸对σ的影响_RS几乎是对于两种类型的凹部的相同，反之，在流水线操作的阶段，影响是不同的。管道尺寸的倾向影响σ _RS稍有不同的凹痕深度增加而增加。多元拟合公式可以提供用于估计σ的参考_RS。