含腐蚀缺陷管道拉伸应变能力预测模型研究

在埋地管道的基于应变设计和评估中，准确和可靠的拉伸应变能力(TSC)预测至关重要。国际管道研究理事会和可靠能源系统中心等研究机构提出的多种TSC预测模型均不适用于具有腐蚀缺陷的管道。鉴于此，本文基于经全尺寸管道拉伸实验验证的广泛参数有限元分析，提出了一种适用于腐蚀管道的TSC预测模型。在所提出的模型中，根据TSC与影响参数之间的相关关系，构建了一个缺陷几何因子函数以描述腐蚀缺陷尺寸(缺陷深度、宽度和长度)对拉伸应变能力的影响。通过非线性回归分析和误差分析验证了所提出模型的准确性和可靠性。结果表明：与有限元结果相比，所提出模型的平均预测误差为5.78%；与实验测试结果相比，模型的最小和最大预测误差分别为3.68%和24.51%；模型的预测范围可以满足应变设计地段腐蚀管道实际安全评估的需求。

Study on the predicted model of tensile strain capacity for pipelines with corrosion defects

Accurate prediction of tensile strain capacity is the key to the strain-based design and assessment of buried pipelines. Various TSC prediction models proposed by research institutions such as the Pipeline Research Council International and the Center for Reliable Energy Systems are not applicable to pipelines with corrosion defects. In view of this, this study proposed a new TSC prediction model for corroded pipes based on extensive parametric finite element analysis validated by full-size pipe tensile tests. In the proposed model, a defect geometry factor function is constructed to describe the effect of corrosion defect size (defect depth, width, and length) on strain capacity based on the correlation between the TSC and the influencing parameters. The accuracy and reliability of the proposed model are verified by nonlinear regression analysis and error analysis. The results show that the average prediction error of the proposed model is 5.78% compared to the finite element results; The minimum and maximum prediction errors of the model were 3.68% and 24.51%, respectively, compared to the experimental test results; The prediction range of the model can meet the needs of the actual safety assessment of the strain design lot corrosion pipeline.