Suspension effect poses a big threat to the integrity and safety of corroded pipelines. In this work, a finite element (FE) based multi-physics field coupling model was developed to determine the mechano-electrochemical (M-E) interaction at an external corrosion defect on a suspended X100 steel pipe and predict its failure pressure. Theoretical calculations were used for model validation. Parameter effects including the defect location on the pipe, geometry of the defect, suspension length and pipe burial depth were determined. Results demonstared that, generally, the M-E effect at corrosion defect caused an increased stress concentration and anodic current density (i.e., corrosion rate), decreasing the failure pressure of the pipeline. The effect became more apparent when the pipe was in suspension. Both the stress and the anodic current density at the corrosion defect were dependent on the defect geometry, especially the defect depth. When the depth was up to 40% of pipe wall thickness, the von Mises stress exceeded the yield stress of the steel, causing local plastic deformation. A critical defect length of $\sqrt{20Dt}$ (D is the outer diameter of the pipe and t is pipe wall thickness) existed, below which the von Mises stress and the anodic current density at the corrosion defect increased with increased defect length. When the defect length exceeded the critical value, the effect was not obvious. An increased suspension length of the pipe would elevate the local stress and anodic current density at the corrosion defect, reducing the failure pressure of the pipe. A critical pipe burial depth of 2.5 m was identified, exceeding which the failure pressure of the pipe decreased rapidly with the increased burial depth. When the burial depth was smaller than 2.5 m, the effect was marginal. The location of the corrosion defect on the pipe did not affect the local stress, anodic current density and failure pressure at an appreciable level, and could be ignored in defect assessment on suspended pipelines.

悬挂效应对腐蚀管道的完整性和安全性构成了巨大威胁。在这项工作中，建立了基于有限元（FE）的多物理场耦合模型，以确定悬架X100钢管在外部腐蚀缺陷下的机械-电化学（ME）相互作用，并预测其失效压力。理论计算用于模型验证。确定了参数影响，包括管道上的缺陷位置，缺陷的几何形状，悬挂长度和管道埋深。结果表明，通常，腐蚀缺陷的ME效应导致应力集中和阳极电流密度（即腐蚀速率）增加，从而降低了管道的破坏压力。当管道处于悬挂状态时，效果会更加明显。腐蚀缺陷处的应力和阳极电流密度都取决于缺陷的几何形状，尤其是缺陷深度。当深度达到管壁厚度的40％时，冯·米塞斯（von Mises）应力超过了钢的屈服应力，从而导致局部塑性变形。关键缺陷长度为$\sqrt{20dŤ}$（D是管道的外径，t是存在管道壁厚），低于此值时，腐蚀缺陷处的von Mises应力和阳极电流密度随缺陷长度的增加而增加。当缺陷长度超过临界值时，效果不明显。管道悬挂长度的增加会增加腐蚀缺陷处的局部应力和阳极电流密度，从而降低管道的破坏压力。管道的临界埋深为2.5 m，超过该深度后，管道的破坏压力会随着埋深的增加而迅速降低。当埋葬深度小于2.5 m时，影响很小。管道上的腐蚀缺陷的位置并没有在一定程度上影响局部应力，阳极电流密度和破坏压力，在悬挂管道的缺陷评估中可以忽略不计。