Finite Element Stress Analysis and Evaluation of the Sealing Performance in Pipe Fittings With Adhesive for Threaded Connections Under Internal Pressure and Bending Moment

2005 ◽  
Author(s):  
Mitsutoshi Ishimura ◽  
Masahide Katsuo ◽  
Toshiyuki Sawa ◽  
Masamichi Serizawa
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Compressive Stress ◽  
Bending Moment ◽  
Fem Analysis ◽  
Pipe Fitting ◽  
3 Dimensional ◽  
Threaded Connections ◽  
Sealing Performance

In practice, PTFE tape is being used for sealing of a pipe fitting. However, the efficiency, the decrease in work time, and the sealing performance can be improved by using adhesive instead of the tape. When such a pipe fitting is under an internal pressure and external bending moment by an internal fluid and others, however, an influence in the sealing performance is taken by how to use an adhesion. This study deals with the stress analysis and the evaluation of the sealing performance of the pipe fitting with an adhesive under an internal pressure and an external bending moment analyzed by using the 3-dimensional elastic finite element method. Furthermore, the experiment of the leakage test of the pipe fitting with an adhesive was carried out when the above loads were applied to the pipe fitting. From 3-D FEM analysis, the following results were obtained: (1) the stress distribution at the interface between thread and adhesive on the side of the internal pressure is tensile stress, and stress on the opposite side is compressive, (2) the stresses at the area of the clearance between the valley of the screw and the mountain increase as the numbers of turns of the thread in fittings increase, and (3) the compressive stress at the side of the tensile part in the fittings decrease as the external bending moments increase. However, the sealing performance will not change when the bending moment is not so great because the compressive stress at the side of the compressive part in the fitting increases. From the leakage tests, the following results of the sealing performance were obtained: (1) the sealing performance of a fittings with adhesive under an internal pressure and a bending moment didn’t decrease when bending moment was not so great, and (2) when it exceeds fixed pressure, rapid leakage from the fitting with adhesive occurred by the exfoliation of the adhesive. Furthermore, the numerical results are in fairly good agreement with the experimental results.

FEM Stress Analysis and Sealing Performance in Pipe Flange Connections With Adhesive Subjected to Internal Pressure and External Bending Moments

2005 ◽  
Author(s):  
Masahide Katsuo ◽  
Toshiyuki Sawa ◽  
Yuki Kikuchi
Keyword(s):  
Internal Pressure ◽  
Stress Analysis ◽  
Bending Moment ◽  
Fem Analysis ◽  
Bending Moments ◽  
3 Dimensional ◽  
Leakage Test ◽  
Sealing Performance ◽  
Flange Thickness ◽  
Good Agreement

This study deals with the stress analysis and the estimation of sealing performance of the pipe flange connections with an adhesive under an internal pressure and an external bending moment are analyzed by using the 3-dimensional elastic finite element method (FEM). The experiment of the leakage test of the connections with an adhesive was carried out by applying the above loads to the connections. From the FEM analysis, the following results were obtained; (1) when an internal pressure is applied to the flange connections, the compressive stress at the interface between a flange and an adhesive increases proportionally from the inner side of the interface to outside, and (2) when an internal pressure and a bending moment apply to the flange connections, the stress distribution at the half part of the interface increases as the external bending moments increase and also Young’s modulus of the adhesive increases. From the experiments, the following results were obtained: (1) sealing performance of the pipe flange connections with an adhesive under an internal pressure and an external bending moment increases as the flange thickness and an initial clamping force of bolts increases and (2) the sealing performances were not found between the connections with an adhesive and that with a gasket combining an adhesive. Furthermore, the numerical results are in fairly good agreement with the experimental results.

Finite Element Stress Analysis for Leak Tests of Pipe Flange Connections Subject to Internal Pressure and Bending Moment

2011 ◽  
Author(s):  
Satoshi Nagata ◽  
Toshiyuki Sawa ◽  
Takashi Kobayashi ◽  
Hirokazu Tsuji
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Bending Moment ◽  
Strain Gages ◽  
Element Analysis ◽  
Element Simulation ◽  
Sealing Performance ◽  
Gas Leak ◽  
Helium Gas

This paper reports the results of finite element analysis representing the sealing performance tests on the slip-on type pipe flange connections for 8 inch and 16 inch. The flange connections are subjected to internal pressure and bending moment. Internal pressure is applied by helium gas and the bending moment is loaded through 4 points bending equipment. Gas leak rates are measured by pressure decay method. During the test, the variations in the axial bolt force are monitored for all the bolts by strain gages. The pipe stress at the junction of pipe and flange is also measured. Finite element analysis simulates the tests and the simulated results are compared with the measured data. Then the behaviors of the slip-on type flange connections under internal pressure and bending moment as well as the sealing performance are clarified by the experiment and the finite element simulation.

FEM Stress Analysis and Leakage Behavior of Pipe-Socket Threaded Joints Subjected to Bending Moment and Internal Pressure

2020 ◽  
Author(s):  
Satoshi Nagata ◽  
Shinichi Fujita ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Bending Moment ◽  
Experimental Tests ◽  
Element Analysis ◽  
Contact Conditions ◽  
Sealing Performance ◽  
Bending Load ◽  
Threaded Joints ◽  
Thread Root

Abstract This paper is a report of the studies on the mechanical behaviors and leakage characteristics of pipe-socket threaded joints subjected to bending moment as well as internal pressure by means of experimental tests and finite element simulations. The paper dealt with the 3/4″ and 3″ joints, and the joints for both sizes have two different combinations of thread types in the pipe and socket, i.e. taper-taper thread combination or taper-parallel one, respectively. Experimental bending leak tests showed that the taper-taper joints could retain internal pressure under bending load up to nearly plastic collapse. The taper-parallel joints, however, could hardly keep internal pressure against bending moment even the sealing tape was applied to enhance the sealing performance. Finite element analysis was carried out to simulate those bending tests, especially to clarify the deformation and the stress distribution in the engaged threads in detail. The analysis demonstrated that the sealing performance of the joints highly depend on the contact conditions not only at the thread crest to thread root but also in between flank surfaces. A complicated leak path across the engaged threads under bending moment was identified by the simulation.

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.

FEM Analysis and an Evaluation of the Sealing Performance in Flexible Box-Shape Flanged Bolted Joints With Gaskets Subjected to Internal Pressure

2006 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Ryo Kurosawa ◽  
Yasuaki Tatsumi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Fem Analysis ◽  
Bolted Joints ◽  
Stress Distributions ◽  
Bolt Preload ◽  
Sealing Performance ◽  
The Difference ◽  
Element Method

The contact gasket stress distributions of rectangular box-shape flange connections with compressed joint sheet gaskets subjected to internal pressure were analyzed taking account hysteresis of the gaskets using finite element method (FEM). Leakage tests were also conducted using actual rectangular box-shape flange connections with compressed joint sheet gaskets under internal pressure. By 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.

Axisymmetrical FEM Analysis and Estimation of the Sealing Performance in Pipe Flange Connections Combining Metallic Gasket With Adhesive Subjected to Internal Pressure and Temperature Change

2002 ◽  
Author(s):  
Masahide Katsuo ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Temperature ◽  
Internal Pressure ◽  
Temperature Change ◽  
Fem Analysis ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Sealing Performance ◽  
Moderately High Temperature

This study deals with the stress analysis and the estimation of the sealing performance of the pipe flange connections combining a metallic gasket with an adhesive subjected to an internal pressure and a temperature change. Stress distributions at the interface between the adherends and the adhesive in the connections are analyzed by using the finite element method (FEM). From the numerical calculations, the following results are obtained: (1) the stress distributes uniformly at the interface except near the edges, (2) the stress increases as Young’s modulus of an adhesive decreases, (3) the stress becomes singular at the edges of the interfaces. In the experiments, the pipe flange connections consisting of dissimilar circular gaskets with an adhesive were manufactured, and the leakage tests of the connections were carried out by applying an internal pressure and a temperature change to the connections. From the experimental results, the following results were obtained: (1) the sealing performance increased as the width of a gasket decreased and the initial clamping stress increased, and (2) the sealing performance of the pipe flange connections subjected to a temperature change increased under a moderately high temperature.

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