Gasketed flange joint is a vital component in pressure vessels and piping systems. Flange joint is usually subjected to bending load due to expansion, wind load, self-weight, etc. Most of the flange design methods use equivalent pressure to include the effect of external bending loads. It becomes complex when the joint is subjected to bending load at elevated temperatures, due to the nonlinear behavior of gasket material. In the present work, performance of the flange joint has been studied under external bending load at elevated temperatures. A 3D finite element model is developed, considering the nonlinearities in the joint due to gasket material and contact between its members along with their temperature dependent material properties. The performance of the joint under different bolt preloads, internal fluid pressures and temperatures is studied. Flange joint with two gaskets (twin gasketed joint) placed beside each other radially, is also analyzed under external bending moment. The maximum allowable bending moments at different internal temperatures, for single and twin gasketed joints with spiral wound gasket are arrived. Copyright © 2015 by ASME.

A. Seshadri Sekhar

Department of Mechanical Engineering

N. Rino Nelson

Bending moments

Bolted joints

finite element method

FLANGES

Machinery

Pipe joints

Pressure vessels

Thermal stress

3D finite element model

Elevated temperature

EXTERNAL BENDING LOADS

FLANGE JOINTS

INTERNAL FLUID PRESSURE

Nonlinearity

Temperature-dependent material properties

Thermal loadings

GASKETS

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Finite element analysis of flange joint with single and twin gaskets under external bending load

American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP

Leakage is the main mode of failure in gasketed flange joints used in nuclear and thermal power plants. The leakage occurs when the joint is not able to withstand the internal fluid pressure. To evaluate the leakage behavior of gasketed flange joint, it is important to incorporate gasket properties and interfacial contact behavior due to friction. However, for safe joint operation, the members also should be structurally sound without exceeding allowable limit of materials. In this study, the joint strength and sealing behavior of gasketed flange joint are investigated through experiments by carrying out leakage test. The joint strength is evaluated based on strains developed in flanges along longitudinal and tangential direction under both pretightening and pressurizing stages. Three-dimensional finite element simulation is also performed under both aforesaid stages, considering the nonlinear properties of gasket along with hysteresis during unloading. The finite element results of joint strength and leakage pressure are compared with experimental values and observed to be conservative. In addition, the performance of twin gaskets (two gaskets concentric to each other) through both experiment and simulation is also evaluated and compared with that of the single gasket. From the experiment and finite element analysis, it is found that the sealability of twin-gasketed joint is higher than that of single-gasketed joint. © IMechE 2017.

Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering

Studies on joint strength and sealing behavior of single and twin-gasketed flange joints

Gasketed flange joints are widely used in pressure vessels and piping systems. They are subjected to bending load due to differential thermal expansion, wind load, self-weight, etc., in addition to assembly and internal fluid load. Most of the flange designs are based on equivalent pressure method to include the effect of external bending loads. The behavior of gasketed flange joint is complex due to the nonlinear hysteretic behavior of gasket material and contact interfaces between joint members. It becomes more complex when the joint is subjected to bending load at elevated temperatures. In the present work, performance of a flange joint has been studied under internal pressure and external bending load at elevated temperatures. A 3D finite element model is developed, considering the nonlinearities in the joint due to gasket material and contact between its members along with their temperature-dependent material properties. The performance of joint under different bolt preloads, internal fluid pressures, and temperatures is studied. Flange joint with two gaskets (twin-gasketed flange joint, TGJ) placed concentric is also analyzed. The results from finite element analysis (FEA) are validated using four-point bending test on gasketed flange joint. The sealing and strength criteria are considered to determine the maximum allowable bending moment at different internal fluid temperatures, for both single- and twin-gasketed flange joints with spiral wound gasket. Twin gasket is able to withstand higher bending moment without leakage compared to single gasket. Results show that the allowable load on flange joint depends on operating temperature and gasket configuration. Copyright © 2017 by ASME.

Journal of Pressure Vessel Technology, Transactions of the ASME

A Study on the Behavior of Single- and Twin-Gasketed Flange Joint under External Bending Load

Gasketed flange joints are usually subjected to internal pressure at high temperature. The most important requirement of flange joint is to provide leak-free joint under operating condition. In the present study, temperature-dependent nonlinear gasket properties of spiral-wound gasket at elevated temperatures are obtained experimentally and included in the analysis. The relaxation of gasket contact stress in both single and twin-gasketed joints at elevated temperatures is compared. It is observed that the ability to withstand internal pressure decreases with increase in temperature in both single and twin-gasketed flange joints. But, the twin-gasketed flange joint is found to withstand higher internal pressure than single-gasketed joint at a given bolt preload and temperature. The influence of gasket seating surface rotation on the distribution of gasket radial contact stress at elevated temperature is studied. The effect of elevated temperature on flange stresses of twin-gasketed joint is also examined. © Institution of Mechanical Engineers.

Effect of thermal loading on sealing behavior of single and twin-gasketed flange joints

ANSYS Mechanical APDL for Finite Element Analysis

Chapter and Section Numbering for Selected ANSYS Mechanical APDL 17.2 Documentation

Volume 2: Computer Technology and Bolted Joints

Effects of Nut Thinning on the Bolt Load Reduction in Bolted Flange Joints Under Internal Pressure and Bending Moments

Journal of Constructional Steel Research

Bending behavior and design model of bolted flange-plate connection

Effects of Scattered Bolt Preload on the Sealing Performance of Pipe Flange Connection With Gaskets Under External Bending Moment and Internal Pressure

Journal	American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
Publisher	American Society of Mechanical Engineers (ASME)
ISSN	0277027X
Open Access	No