The predictions of pipeline burst pressure in the early stage are very importance in order to provide assessment for future inspection, repair and replacement activities. The failure of oil and gas pipelines contribute to economic implications and also constitute a serious hazards to the environment due to leakage. This thesis deals with the study on the effect of corrosion defect on the burst pressure of pipelines for API 5L X42 steel. The objectives for this project are to determine the burst pressure of corroded pipelines using Finite Element Analysis (FEA) and to compare the results with the available pipelines design code. This project implicates analysis of the API X42 steel by using MSC Patran 2008 r1 software as pre-processor and MSC Marc 2008 r1 software as a solver. A quarter of pipe was simulated by fully applying the symmetrical condition. The pipe is modeled in 3-D with outer diameter of 60 mm, wall thickness of 6 mm and different defect parameters. In this analysis, stress modified critical strain used as failure criterion to predict the failure of defective pipe. Result shows that the burst pressure decreases when both defect depth and length increases. The defect depth appear as a most influence parameter that affect the burst pressure. The circumferential extent has a less influence on the burst pressure. The results have been compared to available design codes for corroded pipelines such as ASME B31G, Modified ASME B31G and DNV RP F101. Comparison with available design codes have shown that FEA burst pressure gives higher values compare to codes. From the results, ASME B31G gives the lowest values than other codes.
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机译：早期对管道爆破压力的预测非常重要，以便为将来的检查，维修和更换活动提供评估。石油和天然气管道的故障对经济产生了影响，并且由于泄漏而对环境构成严重危害。本文针对API 5L X42钢的腐蚀缺陷对管道爆破压力的影响进行了研究。该项目的目标是使用有限元分析（FEA）确定腐蚀管道的爆破压力，并将结果与可用的管道设计规范进行比较。该项目通过使用MSC Patran 2008 r1软件作为预处理器和MSC Marc 2008 r1软件作为求解器来分析API X42钢。通过完全应用对称条件来模拟四分之一的管道。该管道以3-D建模，外径为60毫米，壁厚为6毫米，缺陷参数不同。在此分析中，将应力修正的临界应变用作失效准则，以预测有缺陷的管道的失效。结果表明，当缺陷深度和长度都增加时，破裂压力降低。缺陷深度是影响爆破压力的最大影响参数。圆周范围对爆破压力的影响较小。将结果与腐蚀管道的可用设计规范（如ASME B31G，改良的ASME B31G和DNV RP F101）进行了比较。与现有设计规范的比较表明，FEA爆破压力与规范相比具有更高的值。根据结果，ASME B31G给出的值比其他代码最低。
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