Abstract Defect assessment is essential at determination of fitness-for-service of pipelines. While various codes and methods have been developed, none of them focuses on overlapped corrosion defects, especially the investigation of local mechanical-chemical interaction at the overlapped defects. In this work, a finite element-based multi-physics one-way coupling model was developed to simulate and determine the mechano-electrochemical (M-E) interaction at overlapped corrosion defects on an X46 steel pipeline. It is found that the presence of overlapped corrosion defects results in a local stress concentration and enhanced M-E interaction effect on corrosion defect growth. The maximum stress always generates at the corner of the bottom defect. The enhanced M-E interaction causes an accelerated corrosion at the bottom defect, resulting in the rapid defect growth to cause pipeline leaking. The geometry of corrosion defects, especially the defect depth and length, affects local stress concentration and the M-E interaction. With the increasing length and depth of either top or bottom corrosion defects, the overall stress level increases, but the effect is more apparent at the bottom defect. Similarly, the increased M-E interaction due to the increasing length and depth of the corrosion defects results in a more accelerated corrosion at the bottom defect than the top one.

中文翻译：

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重叠腐蚀缺陷处的机械-电化学相互作用建模及其对管道故障预测的影响

摘要 缺陷评估是确定管道服务适用性的关键。虽然已经开发了各种代码和方法，但没有一个专注于重叠腐蚀缺陷，特别是对重叠缺陷处局部机械-化学相互作用的研究。在这项工作中，开发了一种基于有限元的多物理场单向耦合模型来模拟和确定 X46 钢管道上重叠腐蚀缺陷处的机械电化学 (ME) 相互作用。发现重叠腐蚀缺陷的存在导致局部应力集中和增强的 ME 相互作用对腐蚀缺陷生长的影响。最大应力总是在底部缺陷的拐角处产生。增强的 ME 相互作用导致底部缺陷处加速腐蚀，导致缺陷快速增长，导致管道泄漏。腐蚀缺陷的几何形状，尤其是缺陷深度和长度，会影响局部应力集中和 ME 相互作用。随着顶部或底部腐蚀缺陷的长度和深度的增加，整体应力水平增加，但在底部缺陷处影响更明显。类似地，由于腐蚀缺陷的长度和深度的增加，ME 相互作用的增加导致底部缺陷比顶部缺陷加速腐蚀。但在底部缺陷处效果更明显。类似地，由于腐蚀缺陷的长度和深度的增加，ME 相互作用的增加导致底部缺陷比顶部缺陷加速腐蚀。但在底部缺陷处效果更明显。类似地，由于腐蚀缺陷的长度和深度的增加，ME 相互作用的增加导致底部缺陷比顶部缺陷加速腐蚀。