高钢级含腐蚀缺陷管道在复杂载荷下的极限承载力研究

Study on Ultimate Bearing Capacity of High-Grade Steel Pipelines with Corrosion Defects under Complex Loading Conditions

摘要: 针对内压与弯矩耦合作用下含腐蚀缺陷高钢级管道的极限承载力问题，建立了X80管道三维非线性有限元模型，系统分析了径厚比、缺陷深度、长度与宽度等参数对管道失效行为的影响规律。结果表明：随径厚比增大，管道剩余强度呈线性下降，传统ASME B31G准则因未计入弯矩影响，其预测值偏高12%~18%；通过引入径厚比修正因子建立的改进剩余强度模型，可将预测误差降至3%~5%；缺陷几何参数中，深度对极限承载力影响最为显著，极限弯曲应变降幅可达47.6%；基于损伤累积理论与回归分析建立的弯曲应变预测模型，决定系数R²为0.96，验证误差为0.57%。研究成果可为复杂载荷下高钢级含腐蚀缺陷管道的安全评估与运维提供理论依据。

Abstract: To address the issue of the ultimate bearing capacity of high-grade steel pipelines with corrosion defects under the combined action of internal pressure and bending moment, a three-dimensional nonlinear finite element model of an X80 pipeline was established. The influence patterns of parameters such as the diameter-to-thickness ratio, defect depth, length, and width on pipeline failure behavior were systematically analyzed. The results indicate that as the diameter-to-thickness ratio increases, the residual strength of the pipeline decreases linearly. The traditional ASME B31G criterion, which does not account for the influence of bending moment, yields predicted values that are 12%~18% higher. By introducing a correction factor for the diameter-to-thickness ratio, an improved residual strength model was established, reducing the prediction error to 3%~5%. Among the geometric parameters of defects, depth has the most significant impact on the ultimate bearing capacity, with the ultimate bending strain decreasing by up to 47.6%. A bending strain prediction model based on damage accumulation theory and regression analysis was developed, with a coefficient of determination (R²) of 0.96 and a validation error of 0.57%. The research findings provide a theoretical basis for the safety assessment and maintenance of high-grade steel pipelines with corrosion defects under complex loading conditions.