冲击载荷下含腐蚀缺陷的海底管道损伤分析

Damage Analysis of Submarine Pipelines with Corrosion Defects Under Impact Load

针对海底油气管道因冲击和腐蚀易造成管道损伤破坏的问题,基于耦合欧拉-拉格朗日算法(CEL)建立坠物-腐蚀管道-海床土体冲击有限元模型,分析了坠物质量、速度、埋深和腐蚀深度对含腐蚀缺陷管道损伤的影响,并与未腐蚀的完整管道进行了对比。以此为基础,分析了内压和腐蚀深度对撞击后的腐蚀管道应力的影响规律。研究结果表明:含腐蚀缺陷管道受冲击损伤程度均大于完整管道,同等撞击速度、质量和埋深下,冲击损伤值最大分别相差68.6%、14.3%和194.7%;撞击后的腐蚀管道和完整管道最大等效应力均随内压增加而增大,同等内压等效应力值最大相差50.4%;同等腐蚀深度下,未撞击腐蚀管道和撞击后腐蚀管道等效应力值最大相差11.7%。这表明海底油气管道冲击损伤分析应考虑腐蚀缺陷的影响。研究方法及结果可为海底油气管道冲击损伤分析与评价提供参考。

Considering that submarine oil and gas pipelines are susceptible to damage and destruction caused by impact and corrosion,based on the Coupled Euler-Lagrange(CEL)algorithm,a finite element model of falling object-corroded pipeline-seabed soil impact was built to analyze the influence of falling object mass,velocity,buried depth and corrosion depth on the damage of pipeline containing corrosion defects,and a comparison was made with uncorroded intact pipelines.Then,the influence of internal pressure and corrosion depth on the stress of corroded pipelines after impact was analyzed.The results show that the impact damage values of pipelines with corrosion defects are greater than that of intact pipelines.Under the same impact speed,mass and buried depth,the maximum difference in impact damage values is 68.6%,14.3%and 194.7%respectively.The maximum equivalent stress of corroded pipeline and intact pipeline after impact increases with the increase of internal pressure,and the maximum difference in equivalent stress value of the same internal pressure is 50.4%.At the same corrosion depth,the maximum difference in equivalent stress value of non-impacted corroded pipelines and impacted corroded pipelines is 11.7%.This indicates that corrosion defects should be considered when conducting impact damage analysis of submarine oil and gas pipelines.The research method and results provide reference for the impact damage analysis and evaluation of submarine oil and gas pipelines.