Abstract A dent is a common type of defect that occurs during pipeline service. A dented region on a pipe usually creates a strong stress concentration that may become a threat to the safety and integrity of the pipeline. Therefore, such issues are major concerns for pipeline managers. To investigate the strain history behaviour of a dented steel pipeline subjected to increasing internal pressure, a full-scale experimental burst test was performed, and a nonlinear finite element method was used to compare the numerical and experimental results in this study. The paper first discusses the test specimens and test results. Then, the finite element numerical results are verified using the experimental measurement results. Subsequently, the strain behaviour at measurement points and the deformation behaviour of the test pipes were analysed in detail. Furthermore, a sensitivity analysis of strain in the axial and circumferential directions from the dent centre was performed. Deformation analysis reveal that an outward convex phenomenon occurred in axial shoulders on both sides of the dent when the Pipewall Yield Pressure reached. Test results and finite element analysis show that the strain in the dented regions changes rapidly and sharply with a large range, which can easily lead to fatigue under operation pressure for an unconstrained dent.

中文翻译：

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内压持续增加的 API 5L X52 管道凹陷应变响应的实验和数值研究

摘要 凹痕是管道服务过程中常见的缺陷类型。管道上的凹陷区域通常会产生强烈的应力集中，这可能对管道的安全性和完整性构成威胁。因此，这些问题是管道管理人员的主要关注点。为了研究受内压增加的凹陷钢管的应变历史行为，进行了全尺寸试验爆破试验，并使用非线性有限元方法比较了本研究中的数值和试验结果。论文首先讨论了试件和试验结果。然后，使用实验测量结果验证有限元数值结果。随后，详细分析了测量点处的应变行为和试管的变形行为。此外，对从凹痕中心沿轴向和圆周方向的应变进行了敏感性分析。变形分析表明，当管壁屈服压力达到时，凹痕两侧的轴向肩部出现外凸现象。试验结果和有限元分析表明，压痕区域的应变变化迅速、剧烈，变化范围大，容易导致无约束压痕在操作压力下产生疲劳。