Finite Element Analysis on Bolted Flange Connection Subjected to Bending Moment and Thermal Loads
Finite Element Analysis on Bolted Flange Connection Subjected to Bending Moment and Thermal Loads
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弯矩和热载荷作用下螺栓法兰连接的有限元分析
DOI：
10.1115/pvp2005-71463
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
T. Sawa
中科院分区：
文献类型：
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作者：
S. Nagata;T. Sawa
在设计垫圈法兰连接时，应考虑到连接在其工作条件下的实际性能。然而，目前的设计计算方法由于难以解决法兰、螺栓和垫片三体之间的静不确定问题，没有考虑螺栓载荷变化、垫片载荷变化和法兰转动等实际行为。在本文中，作者进行了有限元分析，4英寸螺栓法兰连接与螺旋缠绕垫片插入受弯矩或热负荷以及内压。考虑了垫片加载-卸载曲线的非线性特性。对于弯矩，采用三维有限元模型计算了加压后由于弯矩引起的垫片接触应力分布。将计算得到的垫片接触应力与扩展载荷系数法计算得到的垫片接触应力进行比较，计算出在弯矩作用下法兰连接的性能。本文提出了荷载系数法的扩展，引入了弯矩表示的传统等效压力的概念。对于热载荷，采用轴对称有限元模型计算了法兰连接在高温下的柔性和热膨胀的变化。并对载荷系数法进行了扩展，使其考虑了法兰连接柔性的变化和热膨胀随温度的变化。扩展荷载因子法的计算结果与有限元分析结果进行了核对。ASME版权所有©2005
Gasketed flange connections should be designed taking into consideration the actual behavior of the connections under their operating conditions. However, such actual behaviors as the bolt load change, the gasket load change and the flange rotation are not considered in the current design calculation method due to the difficulty to solve a statically indeterminate problem among three bodies, flanges, bolts and gasket. In this paper, the authors perform finite element analyses on a 4 inch bolted flange connection with a spiral wound gasket inserted subjected to the bending moment or the thermal load in addition to the internal pressure. It is taken into consideration the nonlinearity shown in the loading-unloading curve of the gasket. For the bending moments, the gasket contact stress distribution due to the bending moment after pressurizing is evaluated by using a 3-dimensional FE model. The calculated gasket contact stress is compared with the one obtained from the extended load factor method to calculate the behavior of the flange connection subjected to bending moments. The authors propose the extension of the load factor method incorporating with the concept of the conventional equivalent pressure representing the bending moment. For the thermal load, an axisymmetric FE model is utilized to evaluate the changes in the flexibility and the thermal expansions of the flange connection at the elevated temperature. The authors also extend the load factor method to incorporate with the change of the flexibility of the flange connection and the thermal expansion depending on the change of temperature. The results obtained from the extended load factor method are cross-checked with those from the finite element analysis.Copyright © 2005 by ASME