Studies on joint strength and sealing behavior of single and twin-gasketed flange joints (original) (raw)
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International Journal of Pressure Vessels and Piping, 2006
Performance of a flange joint is characterised mainly by its 'strength' and 'sealing capability'. A number of analytical and experimental studies have been conducted to study these characteristics under internal pressure loading. However, with the advent of new technological trends for high temperature and pressure applications, an increased demand for analysis is recognized. The effect of steady-state thermal loading makes the problem more complex as it leads to combined application of internal pressure and temperature. The present design codes do not address the effects of temperature on the structural integrity and sealing ability. In addition, the available design solutions do not solve problems of failure of a gasketed flange joint even under bolt up and internal pressure loading conditions. To investigate joint strength and sealing capability under combined internal pressure and different steady-state thermal loading, a 3D nonlinear finite element analysis (FEA) of a gasketed flange joint is carried out and its behaviour is discussed. To determine the safe operating conditions or the actual joint load capacity, the joint is further analyzed for different internal pressures keeping the temperature constant. q
Leakage Analysis of Gasketed Flanged Joints Under Combined Internal Pressure and Thermal Loading
ASME 2011 Pressure Vessels and Piping Conference: Volume 3, 2011
Leakage in Gasketed Flanged Joints (GFJs) has always been a great problem for the process industry. The sealing performance of a GFJ depends on its installation and applied loading conditions. This paper aims to finding the leak rate through ANSI class#150 flange joints using a compressed asbestos sheet (CAS) gasket under combined structural and thermal transient loading conditions using two different leak rate models and two different bolt-up levels. The first model is a Gasket Compressive Strain model in which strains are determined using finite element analysis. The other model is based on Porous Media Theory in which gasket is considered as porous media. Leakage rates are determined using both leak rate models and are compared against appropriate tightness classes and the effectiveness of each approach is presented.
2000
Performance of a bolted flange joint is characterized mainly by its’ strength’ and ‘sealing capability’. Performance of bolted flange joints is mostly discussed under steady state loading with and without internal pressure loading. The present design codes also do not address the effects of steady state and thermal transient loading on the joint’s performance. Use of different gaskets also affects the performance of a gasketed joint due to the joint relaxation behavior. In this paper, performance of the gasketed bolted flange joint is analyzed using two different gaskets i.e. solid plate and spiral wound when it is subjected to combined internal pressure and steady state thermal loading using detailed nonlinear finite element analysis.
International Journal of Pressure Vessels and Piping, 2007
Gaskets play an important role in the sealing performance of bolted flange joints, and their behaviour is complex due to nonlinear material properties combined with permanent deformation. The variation of contact stresses due to the rotation of the flange and the material properties of the gasket play important roles in achieving a leak proof joint. In this paper, a three-dimensional finite element analysis (FEA) of bolted flange joints has been carried out by taking experimentally obtained loading and unloading characteristics of the gaskets. Analysis shows that the distribution of contact stress has a more dominant effect on sealing performance than the limit on flange rotation specified by ASME.
International Journal of Mechanics and Materials in Design, 2005
Performance of a flange joint is characterised mainly by its 'strength' and 'sealing capability'. A number of analytical and experimental studies have been conducted to study these characteristics under internal pressure loading. However, with the advent of new technological trends for high temperature and pressure applications, an increased demand for analysis is recognized. The effect of steady-state thermal loading makes the problem more complex as it leads to combined application of internal pressure and temperature. The present design codes do not address the effects of temperature on the structural integrity and sealing ability. In addition, the available design solutions do not solve problems of failure of a gasketed flange joint even under bolt up and internal pressure loading conditions. To investigate joint strength and sealing capability under combined internal pressure and different steady-state thermal loading, a 3D nonlinear finite element analysis (FEA) of a gasketed flange joint is carried out and its behaviour is discussed. To determine the safe operating conditions or the actual joint load capacity, the joint is further analyzed for different internal pressures keeping the temperature constant.
Analysis of Leakage in Bolted-Flanged Joints Using Contact Finite Element Analysis
Journal of Mechanics Engineering and Automation, 2015
The evolution of leakage is studied using detailed contact finite element analysis. The distribution of stress at the gasket is analyzed using a contact condition based on slide-line elements using ABAQUS, a commercial finite element code. Slide-line elements also take into account pressure penetration as contact that is lost between flange and gasket. Results are presented for a particular flange, a raised face flange sealed by a mild steel gasket. A comparison of the results from the gasket contact analysis and the contact conditions specified by the ASME Boiler and Pressure Vessel Code, Sections VIII, Division 1 shows that the conditions specified in the ASME Code predict leakage relatively accurately.
2nd International Conference on Mechanical, Manufacturing and Process Plant Engineering, 2017
Owing to increase in the demand for power, a number of power plants have been installed in the recent past. One of the vital components in these plants is gasketed flange joint. The behaviour of gasketed flange joint is highly dependent on the deformation characteristics of gasket material. In the present study, the deformation characteristic of spiral wound gasket along thickness direction is determined experimentally for different loading rates. Gasket has high nonlinearity under both loading and unloading, with hysteresis. Based on its characteristics, the flange joint is analysed to study its performance and leakage behaviour under static condition. 3D finite element model of flange joint is developed by considering the gasket as interface entity. Finite element analysis of flange joint is performed by including the nonlinear hysteretic behaviour of gasket, under different loading rate and frictional contact between joint members. The influence of different loading and unloading rates is emphasized on the sealing performance of flange joint using leakage pressure. The gasket deforms more when loaded at low rate. This phenomenon also affects the ability to withstand internal fluid without leakage. The maximum safe pressure without leakage increases, when gasket is loaded and unloaded at low rate.
Leakage-cause analysis of a flange joint designed according to standards
Materiali in Tehnologije, 2018
Flange joints and their sealing play an important role in many industries. The gasket performance and its behaviour are influenced by a number of factors, such as non-linear material properties with permanent deformations, assembly procedures and the preparation of sealing surfaces. Additionally, a proper seal function is also affected by the design and strength design of the flanges. Determination of the respective tightening torque needed to achieve a suitable contact pressure between the seal and the flange face is equally important. This paper deals with finite element method (FEM) analyses of a flange joint designed in accordance with the modern standard EN 13445-3 Annex G and examines the influence of operating conditions on the gasket contact pressure. The article also discusses the effects of assembly on the tightness of the joint and the reason for the leakage of the operating medium that took place. The analyses show the effects of operating states on the contact pressures of gaskets and the pre-stressing of bolts. They demonstrate the contact pressure after the application of the pre-stressing of the bolts and its reduction after the temperature-field stabilization due to the start-up of the device. The results of the analyses show that only a relatively small surface of the seal achieves the compression required by the manufacturer to maintain the seal integrity during the application of the tightening forces determined in accordance with EN 13445-3 Annex G. The force of the pre-stressing of the bolts is reduced by approximately 6 % when the normal operation condition is reached. The analyses were performed due to a suspicion of a significant influence of the temperature distribution on flange joints. The main cause of the flange leakage was subsequently revealed by a physical inspection that demonstrated assembly failures when installing gasket 2. The description of these deficiencies is not a subject of this article.