Axi-Symmetrical Stress Analysis and Sealing Performance Evaluation of a Pipe Flange Connection Under Elevated Temperature and Internal Pressure

2012 ◽  
Author(s):  
Yuya Omiya ◽  
Toshiyuki Sawa
Keyword(s):  
Elevated Temperature ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Theory Of Elasticity ◽  
Stress Distributions ◽  
Mechanical Behaviors ◽  
Flange Connection ◽  
Sealing Performance ◽  
The Difference ◽  
Symmetric Theory

The pipe flange connections have been widely used in mechanical structures and these are mainly used under internal pressure and elevated temperature. Some investigations have been performed on mechanical behaviors such as the contact gasket stress distribution of pipe flange connection under internal pressure. However, the effects of elevated temperature on the sealing performance and mechanical behavior in the pipe flange connection have not been analyzed exactly. To design a pipe flange connection, it is necessary to know the effect of elevated temperature and the detailed flange strength for the hub and the contact gasket stress distributions in the connection. In this paper, the stress analysis of a pipe flange connection under elevated temperature and internal pressure is carried out taking into account a non-linearity and hysteresis of the gasket using the axi-symmetric theory of elasticity. The contact gasket stress distributions at the interfaces, the hub stress, in the pipe flange connection under elevated temperature and internal pressure are analyzed. Using the obtained contact gasket stress distributions, the amount of gasket leakage (He gas) is estimated. Leakage tests of the pipe flange connections were also conducted and the temperature of pipe flange connection was measured using thermoelectric couples. As a result, the difference of temperature between inner and outer is about 10%. The contact gasket stress was increased as the heated temperature was increased.

FEM Stress Analysis and an Evaluation of the Sealing Performance in Non-Circular Flange Connections With Gaskets Subjected to Internal Pressure

2006 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Ryo Kurosawa ◽  
Wataru Maezaki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
The Difference

The contact gasket stress distributions of a non-circular flange connection with a compressed sheet gasket subjected to internal pressure were analyzed taking into account of the hysteresis behavior of the gasket by using the finite element method (FEM). Leakage tests were also conducted using an actual non-circular flange connection with a compressed sheet gasket under internal pressure. Using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. The difference in the new gasket constants between the values obtained from the present study and those by the PVRC procedure was substantial. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated.

FEM Stress Analysis and Sealing Performance in Non-Circular Flange Connections With Gaskets Subjected to Internal Pressure

2003 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Wataru Maezaki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Stress Distributions ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Element Method

The contact gasket stress distributions of a non-circular flange connection with a compressed asbestos sheet gasket subjected to internal pressure were analyzed taking account a hysteresis of the gasket by using finite element method (FEM). Leakage tests were also conducted using an actual non-circular flange connection with a compressed asbestos sheet gasket under internal pressure. By using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. A difference in the new gasket constants between the values obtained from the present study and those by the PVRC procedure was substantial. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated. abstract text here.

Stress Analysis and Sealing Performance Evaluation in Rectangular Box-Shape Bolted Flange Connection With Gasket Subjected to Internal Pressure

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Toshiyuki Sawa ◽  
Ryo Kurosawa ◽  
Wataru Maezaki
Keyword(s):  
Finite Element Method ◽  
Internal Pressure ◽  
Research Council ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
The Difference ◽  
Bolted Flange

The contact gasket stress distributions in a rectangular box-shape bolted flange connection with a compressed sheet gasket subjected to internal pressure were analyzed using the finite element method. Leakage tests were also conducted for an actual rectangular box-shape bolted flange connection with a compressed sheet gasket under internal pressure. Using the obtained contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. The difference in the new gasket constants between the values obtained from the present study and those from the Pressure Vessel Research Council (PVRC) procedure was substantial. In addition, a method to determine the bolt preload for a given tightness parameter was demonstrated and the difference in the determined bolt preload was shown between the present study and the PVRC procedure. The characteristics of the rectangular box-shape bolted flange connection were demonstrated by comparing those of circular bolted flange connections.

Stress Analysis and Sealing Performance Evaluation in Non-Circular Flange Connections With Gaskets Subjected to Internal Pressure

2004 ◽  
Author(s):  
Wataru Maezaki ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Performance Evaluation ◽  
Internal Pressure ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
The Difference

The contact gasket stress distributions of a non-circular flange connection with a compressed asbestos sheet gasket subjected to internal pressure were analyzed taking into account of the hysteresis behaviors of the gasket by using the finite element method (FEM). Leakage tests were also conducted using an actual non-circular flange connection with a compressed asbestos sheet gasket under internal pressure. Using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. The difference in the new gasket constants between the values obtained from the present study and those by the PVRC procedure was substantial. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated.

The Sealing Performance of a Large Diameter Bolted Joint Under Elevated Temperature

2007 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Naoki Kawasaki ◽  
Yoshio Takagi ◽  
Hiroyasu Torii
Keyword(s):  
Elevated Temperature ◽  
Internal Pressure ◽  
Large Diameter ◽  
Stress Distributions ◽  
Test Results ◽  
Flange Connection ◽  
Gas Leakage ◽  
Nominal Diameter ◽  
Sealing Performance ◽  
Diameter Pipe

Flange rotation with internal pressure affects the sealing performance of pipe flange connections more with increasing the pipe nominal diameter. Therefore, it is hard to estimate the sealing performance of pipe flange connections with larger nominal diameter by using the test results of the sealing performance for pipe flange connections with small nominal diameter. In this study, the 20" diameter pipe flange connection was experimentally used as a large nominal diameter pipe flange connection and analyzed the stress in the connection. In the experiments, the sealing performance of the pipe flange connection was evaluated by measuring the amount of gas leakage at 50 °C and 100 °C under internal pressure. Non-asbestos graphite gaskets were used in the experiments. The bolts and nuts were tightened according to the Japanese method (HPIS Z103 TR). The gasket contact stress distributions of larger nominal diameter pipe flange connection were calculated by FEM under elevated temperature conditions as well as internal pressure application. The estimated results were compared with the experimental results. The results were also compared with the small nominal diameter test result and discussed.

Sealing Performance Evaluation of Box-Shaped Flange Connections Under Thermal Conduction Conditions and Internal Pressure

2010 ◽  
Author(s):  
Kentaro Tenma ◽  
Ryou Kurosawa ◽  
Toshiyuki Sawa
Keyword(s):  
Elevated Temperature ◽  
Internal Pressure ◽  
Thermal Conduction ◽  
Linear Thermal Expansion ◽  
Stress Distributions ◽  
Flange Connection ◽  
Gas Leakage ◽  
Thermal Expansion Coefficients ◽  
Bolt Preload ◽  
Sealing Performance

Bolted connections with gaskets such as flexible box-shaped flange connections have been used in mechanical structures. The connections are usually used under internal pressure as well as other loadings such as thermal, impact loadings and so on. In designing the bolted flexible box-shaped flange connections with gaskets, it is important to evaluate the sealing performance of the connections under internal pressure and thermal conduction conditions. In this paper, the contact gasket stress distributions and changes in bolt preload in the bolted flexible box-shaped flange connection with compressed sheet gaskets subjected to internal pressure and thermal conduction condition are analyzed using the finite element method (FEM). The leakage tests were conducted using an actual box-shaped flange connection with a compressed sheet gasket. Using the contact gasket stress distributions under internal pressure at an elevated temperature (Helium gas) obtained from the FEM calculations and an amount of the gas leakage measured in the experiment, the sealing performances are evaluated experimentally and numerically. The estimated amount of gas leakage is in a fairly good agreement with the measured results. In addition, the effect of the thermal conduction condition on the sealing performance is examined. Furthermore, the effects of the bolt pitch and the linear thermal expansion coefficients of the flanges and the gasket are examined at elevated temperature (20,80,100°C). Discussion is made on the effects of some factors on the sealing performance.

Thermal Stress Analysis and Evaluation of Sealing Performance in Pipe Flange Connections With Spiral Wound Gaskets Under Elevated Temperature and Internal Pressure

2005 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yoshio Takagi ◽  
Teruhisa Tatsuoka
Keyword(s):  
Thermal Stress ◽  
Elevated Temperature ◽  
Internal Pressure ◽  
Theory Of Elasticity ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Analysis And Evaluation ◽  
Sealing Performance ◽  
Effects Of Temperature ◽  
Spiral Wound

In this paper, the thermal stress distributions at the interfaces between pipe flanges and the gasket under elevated temperature and internal pressure were calculated by using the theory of elasticity and the finite element method (FEM) taking into account hysteresis in the stress-strain curves of spiral wound gasket. Leakage tests were performed using helium gases. In addition, the effects of temperature on the sealing performance were examined by using an actual pipe flange connection with spiral wound gasket under elevated temperature. By using the calculated contact stress distributions and the results of the leakage tests, the sealing performance was evaluated.

Axisymmetric Stress Analysis and Strength Evaluation of Bonded Shrink Fitted Joints of Circular Pipes Subjected to Internal Pressure and Tensile Loads

2000 ◽  
Author(s):  
Masahide Katsuo ◽  
Toshiyuki Sawa ◽  
Masahiro Yoneno
Keyword(s):  
Internal Pressure ◽  
Stress Analysis ◽  
Joint Strength ◽  
Tensile Load ◽  
Theory Of Elasticity ◽  
Shear Stresses ◽  
Stress Distributions ◽  
Strength Evaluation ◽  
Circular Pipes ◽  
Hollow Cylinders

Abstract This study deals with the stress analysis and the strength evaluation of a bonded shrink fitted joint of circular pipes subjected to an internal pressure and a tensile load. In the analysis, two pipes and the adhesive are replaced with finite hollow cylinders, and the stress distributions in the joint are analyzed by using the axisymmetric theory of elasticity. From the numerical calculations, the following results are obtained: (1) Both the compressive and shear stresses at the interface between the adherend and the adhesive increase as Young’s modulus of the adherend increases. (2) The stress becomes singular at the edges of the interfaces. (3) The joint strength can be evaluated using the compressive and shear stresses near the edge of the interface. In the experiments, bonded shrink fitted joints consisting of dissimilar circular pipes were manufactured, and rupture tests of the joints were carried out by applying an internal pressure, and a tensile load to the joints. From the results, the joint strength of the bonded shrink fitted joint was found to be greater than that of the shrink fitted joint. Furthermore, the numerical results are in fairly good agreement with the experimental ones.

Effects of Scatter in Bolt Preload of Pipe Flange Connections With Gaskets on Sealing Performance

2003 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Mitsuhiro Matsumoto ◽  
Satoshi Nagata
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Control Method ◽  
Torque Control ◽  
Stress Distributions ◽  
Flange Connection ◽  
Gas Leakage ◽  
Bolt Preload ◽  
Sealing Performance

It has been well known that a scatter in axial bolt forces of pipe flange connections tightened by the torque control method is substantial. It is necessary for evaluating the sealing performance of the pipe flange connections with the gaskets subjected to intemal pressure to know the contact gasket stress distributions due to the scatter of the axial bolt forces in the connections tightened by the torque control method. This paper deals with the leakage of the pipe flange connections with a spiral wound gasket and that with a compressed sheet gasket tightened by the torque control method. The scatter in the axial bolt forces was measured in the experiments. The contact gasket stress distributions at the interfaces of the pipe flange connections with the gaskets were calculated under the measured axial bolt forces by using elasto-plastic finite element method (FEM) taking into account hysteresis and non-linearity in the stress-strain curves of the gaskets. The effects of the scatter in the axial bolt forces tightened by the torque control method on the gas leakage were also examined by using the actual pipe flange connections. As the result, a difference in an amount of gas leakage measured was found to be substantial between our study and PVRC procedure. By using the calculated contact gasket stress distributions under the internal pressure and the results of the leakage tests, the sealing performance was evaluated. It is found that the sealing performance is worse in the actual pipe flange connection than that evaluated by PVRC procedure.

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