振动与应力作用对管道安全特性的研究

发布时间：2018-04-27 23:03

本文选题：管道系统 + 应力分析　；参考：《兰州交通大学》2017年硕士论文

【摘要】：压力管道是生产过程中极易发生爆裂、泄漏以及疲劳损坏的一种危险性很大的特殊设备,主要应用在石油、化工、冶金、电力以及市政供水供暖和供燃气等各个行业之中。管道的安全运行对我们的生活生产都十分的重要,管道的安全取决于管道应力、振动的有机结合,因此如何在配管后优化管道设置,使应力与振动因素都满足相应的规范要求,这是管道安全评定的关键。本文在管道应力分析的基础上,对工业管道所受的载荷,载荷对管道产生的作用以及失效形式进行了研究。通过梁模型对管道的运行工况进行了力学模拟计算,将计算得到的应力值与管道材料许用应力值进行分析对比,对管系上的不合理结构与设计因素提供优化改进方案。在管道的热应力分析中,提出在配管中不应以最短原则为唯一目标,而是要考虑到管道的热膨胀量引起的位移与推力,利用管道走向形成的L形或Z形自然补偿器的补偿能力来消除热胀载荷对设备与支架的推力。其次,支架的跨距直接决定了持续性载荷下的一次应力是否能够在许用值范围内,最大允许跨距由管道的强度和刚度两个因素决定,取其较小值作为设计依据。最后,存在热应力的立管应力分析中,若采用承重支架,在运行态下分析了各支架节点位置的管道位移,立管处的支架都有不同程度的脱空现象,使支架失效,因此在立管上设置支架应考虑采用弹簧支架。在优化后的管道应力分析满足规范条件的基础上,对管道系统的振动特性进行模拟分析计算,依据计算所得的管道固有频率,对管道系统进行优化调整,避免了工作时管道发生机械共振。所以本文采用有限元分析的方法,并以此为基础运用子空间迭代法求解复杂管道的固有频率。通过分析管道的固有频率与刚度的关系,提出了在管道满足柔性条件的情况下尽量减少弯管的存在以提高管道系统的固有频率。并提出了避免管道发生共振的优化方案,以保障管道系统在安全可靠的条件下运行。
[Abstract]:Pressure pipeline is a kind of special equipment which is easy to burst, leak and fatigue damage in production process. It is mainly used in petroleum, chemical industry, metallurgy, electric power, municipal water supply, heating and gas supply and so on. The safe operation of pipeline is very important to our daily production. The safety of pipeline depends on the organic combination of pipeline stress and vibration. This is the key of pipeline safety assessment. Based on the stress analysis of the pipeline, the paper studies the load, the effect of the load on the pipeline and the failure form of the industrial pipeline. In this paper, the mechanical simulation calculation of pipeline operating condition is carried out through beam model, and the calculated stress value is compared with the allowable stress value of pipe material, which provides an optimized improvement scheme for the unreasonable structure and design factors of pipe system. In the thermal stress analysis of pipeline, it is proposed that the shortest principle should not be regarded as the sole objective, but the displacement and thrust caused by the thermal expansion of the pipeline should be taken into account. The compensation ability of the L-shaped or Z-shaped natural compensator formed by the pipeline strike is used to eliminate the thrust of the thermal expansion load on the equipment and the support. Secondly, the span of the support directly determines whether the primary stress under the sustained load can be within the allowable value, and the maximum allowable span is determined by the strength and stiffness of the pipe, and the smaller value is taken as the design basis. Finally, in the stress analysis of riser with thermal stress, if the load-bearing support is used, the pipeline displacement at the node position of the support is analyzed under the running state, and the support at the riser has different degree of void phenomenon, which makes the support invalid. Therefore, the use of spring support should be considered in the installation of support on the riser. On the basis that the stress analysis of the optimized pipeline meets the requirements of the code, the vibration characteristics of the pipeline system are simulated and calculated, and the pipeline system is optimized and adjusted according to the calculated natural frequency of the pipeline. The mechanical resonance of the pipeline is avoided. In this paper, the finite element method is used to solve the natural frequency of complex pipeline. Based on the analysis of the relationship between the natural frequency and the stiffness of the pipeline, it is proposed to reduce the existence of the curved pipe in order to increase the natural frequency of the pipeline system under the condition that the pipe satisfies the flexible condition. An optimization scheme to avoid pipeline resonance is proposed to ensure the pipeline system to operate under safe and reliable conditions.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U171

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