【作者】 金京福；

【导师】 孙建刚；

【作者基本信息】 大庆石油学院 ， 防灾减灾工程及防护工程， 2007， 硕士

【摘要】 管道运输一直是石油运输的重要方式。大量的管道长期埋置地下,受到内在和外来诸多因素的破坏,随着埋地长输管线服役年限的增加,管线腐蚀情况越来越严重。而石油管材破坏失效的主要原因是内腐蚀,占管道失效事故的30%～50%。因此对内腐蚀管线的剩余强度预测技术进行研究对于制定管线的运行、维修、更换等决策具有重要的意义。首先,本文阐述了管道腐蚀机理和剩余强度评价的历史背景、发展情况,系统地总结了各种管道腐蚀剩余强度评价方法,以及它们的优缺点。其次,用有限元方法对内腐蚀管道的剩余强度进行了分析评估。分析采用了线弹性有限元模型,考虑了几何非线性和材料非线性,采用了线弹性-线性加工强化模型和Bin Fu失效准则,得到了不同腐蚀尺寸对极限荷载的影响以及管壁缺陷处的应力分布状态,以及随内压改变而变化的应力应变图。同时利用Matlab、SPSS数据处理软件对所得的最大内压进行非线性最小二乘估算法的回归分析,拟合出了一个轴向内腐蚀极限荷载的回归方程,并把有限元分析的结果和现在的准则进行比较。研究表明用回归方程得出的轴向内腐蚀极限荷载与有限元结果比较接近,在一定程度上克服了B31G准则的保守性,说明拟合得出的回归方程具有一定的精确度。再次,以内腐蚀管道最大极限压力为评价出发点,提出内腐蚀缺陷剩余强度评价的分级评价方法,建立了管道腐蚀缺陷的多级评价体系。以局部腐蚀管线为例,对腐蚀缺陷进行分级评价。更多还原

【Abstract】 Pipeline transportation is the important way of petroleum transportation all long. Most of pipelines are embedded in the underground; they are damaged by factors of inner and outer. With the increase of service year of long transportation underground pipeline, pipelines corrosion has become more and more serious. However, the prime reason in failure factors of pipeline is the internal corrosion which reaches to 30%~50% in the pipeline failure. So the study for the pipelines residual strength of corroded pipelines has important significance for the decision-making of the function, servicing and replacing of the pipelines.Firstly, this paper sets forth in brief the background and development of the residual strength assessment technology and the theory of corroded pipeline, summarizes various assessment methods of corroded pipeline as well as their advantages and disadvantages.Secondly, the Finite Element was performed on the assessment and study of residual strength of corroded pipeline. Liner-elastic finite element is adopted. Geometrical nonlinearity and material nonlinearity is considered by using linear elastic-linearity hardening mode and Bin Fu failure criterion. The influences of the limit load of pipeline which various corrosion sizes and stress distribution status at the defect of pipeline is obtained. The figure of strain and stress with the inner-pressure is obtained. At the same time, the largest inner-pressure is analyzed with the non-liner least square estimation method by MATLAB and SPSS software. And a fitted multiple regression equation on the limit load of pipeline with axial internal corrosion is deduced. The result of Finite Element Analysis and that of existed criteria are compared. The study indicate that the results of the limit load of the pipeline corroded inside in one axes that are calculated by the fitted multiple regression equation are almost equal to the results by the finite element method. And the conservative of the criterion B31G is conquered in a certain extent. Forecasted results are parallel with the results of finite element method and are accurate.Finally, taking the maximum allowing operation pressure (MAOP) as assessment rule the new method of the residual strength assessment of various inside corrosion is put forward .The multilevel assessment system of corrosion defects is established. Taking local corroded pipeline for example, evaluate the corrosion defects by classification.更多还原