无石棉垫片本构方程的建立及性能研究

发布时间：2018-06-19 21:52

本文选题：螺栓法兰系统 + 无石棉垫片　；参考：《昆明理工大学》2014年硕士论文

【摘要】：垫片螺栓接头是压力管道、压力容器应用最广泛的可拆式连接。垫片作为其中的过渡元件与相邻法兰的结合面形成紧密的接触,提供连接必须的密封,它的性能将直接影响整个接头的可靠性。本文利用有限元法,在不同内压和温度条件下,对整个接头系统进行了数值模拟分析。主要研究内容如下： 1.对无石棉垫片的抗拉强度、压缩回弹性、耐介质性、密封性展开了进一步的研究。 2.根据无石棉底片具有非线性黏弹性的特点,构造了常温下无石棉垫片的蠕变松弛数学模型,并用试验对所构造的数学模型进行了验证。结果表明本文提出的数学模型可以用来预测垫片在常温下的行为特性。进而,垫片应力水平和垫片厚度对垫片常数的影响在该模型中也得到了进一步的研究。 3.考虑了垫片材料的非线性和接触非线性建立了垫片螺栓接头的三维力学模型及传热学模型。 4.利用ABAQUS软件对垫片螺栓接头的温度场、应力场进行了模拟研究。分析得出：a)螺栓、法兰和垫片的温度分布；b)法兰转角与螺栓、垫片的应力关系；c)垫片周向和轴向方向上的应力分布；d)在耦合状态下温度对应力的影响等。法兰接头的性能主要是其强度和密封能力,在内压工况下对其性能的分析和试验研究已经很成熟拉,但是随着高温高压设备的普及应用,对其接头的性能要求就越高。目前的设计规范中并未考虑温度对整个结构强度和密封能力的影响,本文对高温高压下螺栓法兰接头的强度和密封能力进行了研究,以此来确定其安全操作条件或接头的载荷能力。所得出的规律对于垫片螺栓接头的强度和密封能力设计具有一定的指导意义。
[Abstract]:Gasket bolt joint is a pressure pipe, pressure vessel is the most widely used detachable connection. The gasket acts as the transition element and forms close contact with the joint surface of the adjacent flange, which provides the necessary sealing for the connection, and its performance will directly affect the reliability of the whole joint. In this paper, the finite element method is used to simulate the whole joint system under different internal pressure and temperature. The main contents are as follows: 1. In this paper, the tensile strength, compression resilience, medium resistance and sealing property of stone free cotton pad are further studied. 2. According to the nonlinear viscoelastic characteristics of asbestos-free negatives, a creep relaxation mathematical model of asbestos-free cotton pads was constructed at room temperature, and the mathematical model was verified by experiments. The results show that the proposed mathematical model can be used to predict the behavior of gasket at room temperature. Furthermore, the effects of gasket stress level and gasket thickness on the gasket constant are further studied in this model. Considering the nonlinear and contact nonlinearity of gasket material, the three-dimensional mechanical model and heat transfer model of gasket bolt joint are established. 4. The temperature field and stress field of gasket bolt joint were simulated by Abaqus software. The temperature distribution of the bolt, flange and gasket is analyzed. The relationship between the angle of flange and the bolt, the stress relation of the gasket, the stress distribution in the circumferential and axial direction of the gasket is obtained, and the effect of temperature on the stress under the coupling state is obtained. The performance of flange joint is mainly its strength and sealing ability. The analysis and experimental study on the performance of flange joint under internal pressure condition is very mature. However, with the popularization and application of high temperature and high pressure equipment, the higher the performance requirement of the joint is. The influence of temperature on the strength and sealing ability of the bolted flange joint is not considered in the current design code, and the strength and sealing ability of the bolt flange joint under high temperature and high pressure are studied in this paper. In order to determine its safe operating conditions or joint load capacity. The obtained rule has certain guiding significance for the design of strength and sealing ability of gasket bolt joint.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH131

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