法兰螺栓连接系统下密封垫片的蠕变性能

发布时间：2018-04-24 21:54

本文选题：法兰螺栓连接系统 + 垫片　；参考：《昆明理工大学》2011年硕士论文

【摘要】：法兰螺栓连接系统是石油化工设备、航天技术等领域运用最广泛的连接装置,垫片是连接系统中最重要的密封元件,它直接影响连接系统密封的可靠性。为了防止由于垫片性能而造成法兰接头的密封失效,把法兰、螺栓和密封垫片看成一个整体作为研究对象,具有重要的意义。首先,运用粘弹性理论建立了适合非金属密封垫片的蠕变松弛数学模型,并解析出了蠕变变形量和时间的关系式。本文把法兰接头的各元件看成一个系统,并考虑垫片的非线性,建立了1/2法兰接头的参数化有限元模型,分析了法兰螺栓连接系统在预紧力的作用下、不同内压的工况下应力分布情况和螺栓的应力分布情况。研究表明,垫片的应力分布规律基本一致,且随着内压载荷的升高,同一部位的应力强度数值相应增大,此时在法兰与封头连接处出现了最大的应力强度,这与实际的情况是一致的。其次,分析了螺栓在不同温度下的应力松弛性能,并与PVRC中应力松弛试验数据比较,发现两者的结果较为接近；并对应力松弛导致的再次拧紧时间进行讨论,并和实验的结果进行了比较,两者较吻合。最后,分析了在不用预紧力情况下的密封垫片的蠕变性能,得出了垫片变形量和时间的关系曲线,并和实验数据进行了对比,两者的结果接近；还分析了不同厚度下垫片的蠕变变形对法兰接头紧密性的影响,得出随着垫片厚度越大,垫片的蠕变量会相应的增加。
[Abstract]:The flange bolt connection system is the most widely used connection device in petrochemical equipment, aerospace technology and so on. The gasket is the most important sealing element in the connection system, which directly affects the reliability of the connection system seal. In order to prevent the sealing failure of flange joint due to the performance of gasket, it is of great significance to regard flange, bolt and seal gasket as a whole as the object of study. Firstly, a mathematical model of creep relaxation suitable for non-metallic seal gaskets is established by using viscoelastic theory, and the relationship between creep deformation and time is analyzed. In this paper, the components of flange joint are regarded as a system, and considering the nonlinearity of gasket, the parametric finite element model of 1 / 2 flange joint is established, and the flange bolt connection system is analyzed under the action of pretightening force. Stress distribution and bolt stress distribution under different internal pressure conditions. The results show that the stress distribution of the gasket is basically the same, and with the increase of the internal pressure load, the stress intensity of the same position increases accordingly, and the maximum stress intensity appears at the joint between the flange and the head. This is in line with the actual situation. Secondly, the stress relaxation properties of bolts at different temperatures are analyzed, and compared with the stress relaxation test data in PVRC, it is found that the results are close, and the re-tightening time caused by stress relaxation is discussed. The results are in good agreement with the experimental results. Finally, the creep performance of the gasket without preload is analyzed, and the relationship between the deformation of the gasket and the time is obtained, and the results are compared with the experimental data, and the results are close to each other. The influence of creep deformation of gasket on the tightness of flange joint is also analyzed. It is concluded that the creep of gasket increases with the thickness of gasket.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH136

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