Multiple corrosion defects located in varied orientations are common on pipelines, significantly impacting pipeline conditions. In this work, 3D finite element (FE) based multi-physics field coupling models were developed to model mechano-electrochemical (M−E) interaction between corrosion defects with varied orientations and its effect on pipeline conditions. The effects of the parameters, including defect geometries, operating conditions, and the relative positions and spacings between the defects, were determined. The results demonstrated that, the strongest M−E interaction occurred between defects when the longitudinal or circumferential spacing is 0, causing high-level local stress concentration and the anodic current density (i.e., corrosion rate) at the corrosion defects. As the defects gradually overlapped or separated from each other on the pipe surface, the magnitude of the M−E interaction decreased. The interaction between defects even disappeared when the longitudinal or circumferential spacing between defects reached 96 mm or 72 mm, respectively, and the defects can be assessed separately. An increased internal pressure led to local plasticity deformation and anodic current density concentration occurring at the inner edge of the defects and defect adjacent area. For example, the maximum anodic current density increased by 56.4% when the internal pressure increased from 12 MPa to 17 MPa. It was also observed that M−E interaction between defects disappeared if the defects were shorter than 48 mm or shallower than 8 mm. Sensitivity analysis demonstrated that the degree of M−E interaction was most sensitive to circumferential spacing, followed by defect depth, defect length, longitudinal spacing, and internal pressure.

位于不同方向的多个腐蚀缺陷在管道上很常见，显着影响管道状况。在这项工作中，开发了基于 3D 有限元 (FE) 的多物理场耦合模型来模拟不同方向的腐蚀缺陷之间的机械-电化学 (ME) 相互作用及其对管道条件的影响。确定了参数的影响，包括缺陷几何形状、操作条件以及缺陷之间的相对位置和间距。结果表明，当纵向或周向间距为 0 时，缺陷之间发生最强的 M-E 相互作用，导致腐蚀缺陷处出现高水平的局部应力集中和阳极电流密度（即腐蚀速率）。随着缺陷在管道表面逐渐重叠或相互分离，ME 相互作用的幅度减小。当缺陷之间的纵向或周向间距分别达到 96 mm 或 72 mm 时，缺陷之间的相互作用甚至消失，并且可以单独评估缺陷。内部压力增加导致局部塑性变形和阳极电流密度集中发生在缺陷的内边缘和缺陷邻近区域。例如，当内部压力从 12 MPa 增加到 17 MPa 时，最大阳极电流密度增加了 56.4%。还观察到，如果缺陷短于 48 毫米或浅于 8 毫米，则缺陷之间的 M-E 相互作用消失。