A Stress Analysis of Pipe Flange Connections Subjected to External Bending Moments

In designing pipe flange connections with gaskets, it is important to know the interface stress distributions between the gasket and the flanges from preventing leakage accident. Especially, when an internal pressure and an external bending moment are applied to the connections, an additional axial bolt force Ft is occurred and the interface stress distributions are changed. From the bolt design standpoint, it is necessary to estimate the ratio of the additional axial bolt force Ft to the external load, that is, the load factor. In this paper, the stress of pipe flange connections with flat-face gasket is analyzed by using axi-asymmetric theory of elasticity and FEM. In addition, the load factor is also analyzed. The stress of pipe flange connections with raised-face gaskets is analyzed by using FEM. Experiments were carried out to measure the load factor and the bolt bending stress. The numerical results are compared with the experimental results. Some considerations are made on the characteristics of pipe flange connections.