Dental defect is one of the most typical mechanical damage to pipelines. Consequently, the investigation of dented-pipeline performance at the service and shut-down phases is therefore critical to the integrity of the pipelines. In practice, dent defects tend to re-round due to the influence of internal pressure. Therefore, in this paper, the influence of the internal pressure on the dent re-rounding is investigated. Three-dimensional finite element (FE) model is established to simulate the indentation and re-rounding process of the dented pipeline. The numerical model was firstly validated against the experimental test data founded in the literature. Thereafter, a comprehensive parametric study on the key geometrical and operational parameters was investigated. The effects of pipe wall thickness, indenter geometry, internal pressure and dent depth on the re-rounding behavior of the dented pipelines in the service and shutdown stages were studied. The FE results demonstrated that a thicker wall thickness of the pipeline or a larger indenter tends to cause less re-rounding of the dented pipeline. Besides, the re-rounding behavior of the dented pipeline is strongly affected by the amplitude of the internal pressure. The parametric study on the magnitude of the re-rounding coefficients of the running dented pipeline (at service stage) and during the maintenance period (at shutdown stage) was in the range of 1.0–1.9 and 1.0–1.4, respectively. Thereafter, a nonlinear regression analysis was carried out to establish a new parametric equation of the dent re-rounding coefficients.

牙齿缺陷是对管道最典型的机械损伤之一。因此，因此，在服务和关闭阶段对降低的管道性能进行调查对于管道的完整性至关重要。实际上，由于内部压力的影响，凹痕缺陷倾向于重新磨圆。因此，本文研究了内部压力对凹痕回圆的影响。建立三维有限元（FE）模型，以模拟凹陷管道的压痕和重新修圆过程。首先根据文献中建立的实验测试数据对数值模型进行了验证。此后，对关键几何和操作参数进行了全面的参数研究。管壁厚度，压头几何形状，研究了内部压力和凹痕深度对服务和停机阶段凹陷管道重新圆化行为的影响。有限元分析结果表明，较厚的管道壁厚或较大的压头往往会导致凹陷的管道变圆。此外，凹陷管道的重新修整行为还受到内部压力幅度的强烈影响。正在运行的凹陷管道（在服务阶段）和维护期间（在停机阶段）的回合系数的大小的参数研究分别在1.0–1.9和1.0–1.4的范围内。此后，进行了非线性回归分析，以建立新的凹痕舍入系数参数方程。