高温高压下深水海底管线水平向整体屈曲研究
发布时间：2019-06-13 20:05
【摘要】：在深海油气工程中,海底管线系统十分庞大,被称为海洋油气资源输送的生命线。高温高压下裸置海底管线的水平向整体屈曲是管线破坏的主要形式之一,是深海油气开发面临的重要技术挑战。较大的屈曲变形一方面可能导致管线中的弯曲应力增长,接近或达到材料的屈服强度,对管线的安全运营造成威胁;另一方面可能造成管线配重层、保温层结构破坏,影响管线的正常使用。因此开展高温高压下海底管线的水平向整体屈曲研究具有重要的理论意义和工程实用价值。本文基于土体对管线约束力的常系数模型,运用解析解和显式动力数值方法分析了理想管线、含单一几何初始缺陷管线和含非单一几何初始缺陷管线的水平向整体屈曲特性,阐明了管线整体屈曲研究中的若干关键性问题。主要研究工作和创新性成果如下:(1)提出了基于大变形理论的整体屈曲解析分析方法,验证了该方法的准确性,推导了理想和含单一几何初始缺陷管线高阶模态整体屈曲的解析解。工程实例分析表明,理想管线发生低阶模态整体屈曲时ModelⅡ较ModelⅠ更易发生;发生高阶模态整体屈曲时ModelⅣ较ModelⅢ更易发生;含单拱缺陷管线更易发生ModelⅠ的整体屈曲;含双拱缺陷的管线更易发生ModelⅡ的整体屈曲。(2)推导了管线最优模型长度的计算公式,揭示了几何初始缺陷较小时屈曲变形出现动态跳转现象的本质。研究表明,管线最优模型长度的大小随初始缺陷幅值与波长比值的增加而减小,管线屈曲段内轴力释放量先大于后小于滑动段土阻力的增加量是动态跳转产生的主要原因。(3)提出了模态分析与显示动力相结合的数值模拟方法,实现了三维实体地基单元上管线整体屈曲的模拟。对比了几何初始缺陷和干扰力激发管线发生水平向整体屈曲的区别与联系。研究表明,运用显示动力法模拟海底管线的整体屈曲具有可靠性,几何初始缺陷和干扰力均可诱发管线发生整体屈曲,两种方法没有直接的对应关系,得到的分析结果存在偏差。(4)开展了理想管线、含单一和非单一几何初始缺陷管线水平向整体屈曲的数值模拟,对比了数值模拟结果与解析解结果的区别,揭示了缺陷间距及组合方式对整体屈曲计算结果的影响。工程算例分析表明,管线整体屈曲的变形形态不是独立的,是由低阶向高阶发展的过程;解析解与数值模拟结果的差异随vom/L0的增加而逐渐减小;缺陷间距较小时,会出现屈曲叠加现象,不利于管线的稳定。
[Abstract]:In deep-sea oil and gas engineering, the submarine pipeline system is very large, which is called the lifeline of offshore oil and gas resources transportation. Horizontal global buckling of bare submarine pipelines under high temperature and high pressure is one of the main forms of pipeline failure and is an important technical challenge for deep-sea oil and gas development. On the one hand, the large buckling deformation may lead to the increase of bending stress in the pipeline, approaching or reaching the yield strength of the material, which may threaten the safe operation of the pipeline; on the other hand, it may cause the damage of the weight layer and insulation layer of the pipeline, which may affect the normal use of the pipeline. Therefore, it is of great theoretical significance and practical value to carry out the study of horizontal global buckling of submarine pipelines under high temperature and high pressure. In this paper, based on the constant coefficient model of soil binding force on pipelines, the horizontal global buckling characteristics of ideal pipelines, pipelines with single geometric initial defects and pipelines with non-single geometric initial defects are analyzed by means of analytical solution and explicit dynamic numerical method, and some key problems in the study of global buckling of pipelines are expounded. The main research work and innovative results are as follows: (1) the analytical analysis method of global buckling based on large deformation theory is proposed, the accuracy of this method is verified, and the analytical solutions of high-order mode global buckling of pipelines with ideal and single geometric initial defects are derived. The analysis of engineering examples shows that Model II is more likely to occur in low-order mode global buckling than Model 鈪，
本文编号：2498785
[Abstract]:In deep-sea oil and gas engineering, the submarine pipeline system is very large, which is called the lifeline of offshore oil and gas resources transportation. Horizontal global buckling of bare submarine pipelines under high temperature and high pressure is one of the main forms of pipeline failure and is an important technical challenge for deep-sea oil and gas development. On the one hand, the large buckling deformation may lead to the increase of bending stress in the pipeline, approaching or reaching the yield strength of the material, which may threaten the safe operation of the pipeline; on the other hand, it may cause the damage of the weight layer and insulation layer of the pipeline, which may affect the normal use of the pipeline. Therefore, it is of great theoretical significance and practical value to carry out the study of horizontal global buckling of submarine pipelines under high temperature and high pressure. In this paper, based on the constant coefficient model of soil binding force on pipelines, the horizontal global buckling characteristics of ideal pipelines, pipelines with single geometric initial defects and pipelines with non-single geometric initial defects are analyzed by means of analytical solution and explicit dynamic numerical method, and some key problems in the study of global buckling of pipelines are expounded. The main research work and innovative results are as follows: (1) the analytical analysis method of global buckling based on large deformation theory is proposed, the accuracy of this method is verified, and the analytical solutions of high-order mode global buckling of pipelines with ideal and single geometric initial defects are derived. The analysis of engineering examples shows that Model II is more likely to occur in low-order mode global buckling than Model 鈪，
本文编号：2498785
本文链接：https://www.wllwen.com/kejilunwen/shiyounenyuanlunwen/2498785.html
