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

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
N. Rino Nelson ◽  
N. Siva Prasad ◽  
A. S. Sekhar
Keyword(s):  
Finite Element ◽  
Elevated Temperatures ◽  
Bending Moment ◽  
Pressure Vessels ◽  
Hysteretic Behavior ◽  
Bending Test ◽  
Flange Joint ◽  
Internal Fluid ◽  
Bending Load ◽  
Gasket Material

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.

Finite Element Analysis of Flange Joint With Single and Twin Gaskets Under External Bending Load

2015 ◽  
Author(s):  
N. Rino Nelson ◽  
N. Siva Prasad ◽  
A. S. Sekhar
Keyword(s):  
Finite Element ◽  
Work Performance ◽  
Elevated Temperatures ◽  
Bending Moment ◽  
Element Model ◽  
Pressure Vessels ◽  
Flange Joint ◽  
Element Analysis ◽  
Bending Load ◽  
Gasket Material

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.

Finite Element Analysis of Local Inelastic Strain Based on Stress Redistribution Locus

2008 ◽  
Author(s):  
Shunji Kataoka ◽  
Takuya Sato
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Loading ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Pressure Vessels ◽  
Stress Redistribution ◽  
Strain Diagram ◽  
Element Analysis ◽  
Inelastic Analysis

Creep-fatigue damage is one of the dominant failure modes for pressure vessels and piping used at elevated temperatures. In the design of these components the inelastic behavior should be estimated accurately. An inelastic finite element analysis is sometimes employed to predict the creep behavior. However, this analysis needs complicated procedures and many data that depend on the material. Therefore the design is often based on a simplified inelastic analysis based on the elastic analysis result, as described in current design codes. A new, simplified method, named, Stress Redistribution Locus (SRL) method, was proposed in order to simplify the analysis procedure and obtain reasonable results. This method utilizes a unique estimation curve in a normalized stress-strain diagram which can be drawn regardless of the magnitude of thermal loading and constitutive equations of the materials. However, the mechanism of SRL has not been fully investigated. This paper presents results of the parametric inelastic finite element analyses performed in order to investigate the mechanism of SRL around a structural discontinuity, like a shell-skirt intersection, subjected to combined secondary bending stress and peak stress. This investigation showed that SRL comprises a redistribution of the peak and secondary stress components and that although these two components exhibit independent redistribution behavior, they are related to each other.

Experimental Determination of the Ultimate Strength of Box Girder Specimens

2016 ◽  
Author(s):  
Thomas Lindemann ◽  
Patrick Kaeding ◽  
Eldor Backhaus
Keyword(s):  
Finite Element ◽  
Experimental Determination ◽  
Ultimate Strength ◽  
Progressive Collapse ◽  
Bending Moment ◽  
Element Model ◽  
Experimental Results ◽  
Bending Test ◽  
Box Girder

The Finite Element Method (FEM) is a feasible tool to perform progressive collapse analyses of large structural systems. Despite enormous developments in finite element formulations and computer technologies the results of structural analyses should be validated against experimental results. In this paper the collapse behaviour of two identical box girder specimens is determined experimentally for the load case of pure longitudinal bending. The specimens are composed of stiffened plate panels and connected at either ends to a loading structure. Within a 4-point bending test a constant bending moment is applied to each specimen to determine the collapse behaviour even in the post-ultimate strength range. The results of the experimental determination of the ultimate strength are presented for the box girder specimens. To simulate the collapse behaviour a finite element model is used and validated against experimental results.

scholarly journals Semi-continous beam-to-column joints for slim-floor systems in seismic zones

2018 ◽  
Author(s):  
Adrian Ciutina ◽  
Cristian Vulcu ◽  
Rafaela Don
Keyword(s):  
Finite Element ◽  
Concrete Slab ◽  
Bending Moment ◽  
Steel Structures ◽  
Bending Test ◽  
Steel Beams ◽  
Element Analysis ◽  
Natural Fire ◽  
Floor Systems ◽  
Moment Resisting

The slim-floor building system is attractive to constructors and architects due to the integration of steel beam in the overall height of the floor, which leads to additional floor-to-floor space, used mostly in acquiring additional storeys. The concrete slab offers natural fire protection for steel beams, while the use of novel corrugated steel sheeting reduces the concrete volume, and replaces the secondary beams (for usual spans of steel structures). Currently the slim-floor solutions are applied in non-seismic regions, and there are few studies that consider continuous or semi-continuous fixing of slim-floor beams. The present study was performed with the aim to develop reliable end-plate bolted connections for slim-floor beams, capable of being applicable to buildings located in areas with seismic hazard. It is based on numerical finite element analysis, developed in two stages. In a first stage, a finite element numerical model was calibrated based on a four point bending test of a slim-floor beam. Further, a case study was analysed for the investigation of beam-to-column joints with moment resisting connections between slim-floor beams and columns. The response was investigated considering both sagging and hogging bending moment. The results are analysed in terms of moment-rotation curve characteristics and failure mechanism. 

scholarly journals Finite element analysis of dovetail joint made with the use of CNC technology

2010 ◽  
Vol 58 (5) ◽  
pp. 321-328 ◽  
Author(s):  
Václav Sebera ◽  
Milan Šimek
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Models ◽  
Experimental Testing ◽  
Joint Stiffness ◽  
Bending Moment ◽  
Parametric Models ◽  
Cnc Machine ◽  
Element Analysis ◽  
Bending Load

The objective of the paper is the parametrization and the finite element analysis of mechanical pro­per­ties of a through dovetail joint made with the use of a specific procedure by a 3-axis CNC machine. This corner joint was used for the simulation of the bending load of the joint in the angle plane – by compression, i.e. by pressing the joint together. The deformation fields, the stress distribution, the stiffness and the bending moment of the joints were evaluated. The finite element system ANSYS was used to create two parametric numerical models of the joint. The first one represents an ideal­ly stiff joint – both joint parts have been glued together. The second model includes the contact between the joined parts. This numerical model was used to monitor the response of the joint stiffness to the change of the static friction coefficient. The results of both models were compared both with each other and with similar analyses conducted within the research into ready-to-assemble furniture joints. The results can be employed in the designing of more complex furniture products with higher demands concerning stiffness characteristics, such as furniture for sitting. However, this assumption depends on the correction of the created parametric models by experimental testing.

Deformation Behavior of Bellows Pipes for Laying Cables Under Ground by Axial Load and Bending Moment

2005 ◽  
Author(s):  
Satoshi Tehara ◽  
Hisashi Naoi ◽  
Hideki Okada ◽  
Makoto Osaku
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Deformation Behavior ◽  
Axial Load ◽  
Bending Moment ◽  
Bending Test ◽  
Ground Subsidence ◽  
Buried Pipe ◽  
Element Method

Recently, electricity demand is rising steeply with advance of science. Additionally quantity of cables such as telephone and optical fiber is rising with communications development and increase of residence. These cables are untidily wired in the air with telephone pole. They impair cityscape and disturb pedestrian safety. Therefore improvement of procedures installing cables is requested. In order to solve it, the plan [1] which buries cables protected in pipes under ground is progressing. They are called buried pipes and consist of straight pipe made from stainless steel or plastic. However there is concern that the buried pipe is crushed and broken by the complex load due to earthquake and ground subsidence. Thus, it is necessary to develop the buried pipe with function of flexibly against damage or rupture. We focus attention to U-type bellows pipe with function of flexibly. In this study, we conduct tensile, compressive, bending test and numerical analysis of those tests using finite element method. From result, we investigate for the relationship between mechanical characteristic and deformation behavior. We study application of bellows pipe to buried pipe. In this study, we examined and analyzed deformation behavior when axial load and bending moment were given to specimens. Examinations items are as (1) we measured load, elongation bending radius by using are experimental device which modeled ground subsidence. (2) We obtained deformation behavior by numerical analysis by using constituted equations of solid mechanics. (3) We conducted simulation analysis of models constructed by finite element method. By comparing these three items, the deformation behavior is clarified.

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.

Explicit Dynamic Simulation of High Density Polyethylene Beam under Flexural Loading Condition

2012 ◽  
Vol 229-231 ◽  
pp. 2150-2154 ◽  
Author(s):  
M. Khalajmasoumi ◽  
S.S.R. Koloor ◽  
A. Arefnia ◽  
I.S. Ibrahim ◽  
J. Mohd Yatim
Keyword(s):  
Finite Element ◽  
Mechanical Behaviour ◽  
Mechanical Analysis ◽  
Polymer Materials ◽  
Bending Test ◽  
Complex Deformation ◽  
Bending Load ◽  
Tension And Compression ◽  
Stress And Deformation ◽  
Explicit Dynamic

Improve stability and reliability of machine components has confirmed the necessary needs of using advance materials such as polymers and composites. Specific characterization of polymer materials can improve the altitude of products design by increasing the mechanical feature of structures such as high fatigue strength, longer life and etc. Polymers are known as hyperelastic materials with a complicated mechanical behaviour. An acceptable mechanical analysis of three dimensional (3D) polymer structures depends on a true understanding of applied model on computational methods such as Finite Element Method (FEM). This study focused on stress and deformation analysis of 3D polyethylene polymer panel under three-point bending test using FEM. Explicit dynamic procedure has been used to examine the mechanical behaviour of polymer beam. Two tests of tension and compression is performed on polymer specimens to extract the material properties and used in finite element model. The specimen panel selected thick enough to generate two complicated situation of tension and compression zone while it is under bending load condition. The test was performed to extract the actual response of the specimen by plotting the force-deflection curve and stiffness of structure. The experimental data confirmed well the simulation results and states the accuracy of the analysis process. A discussion is given on effective stress and deformation generated in the polymer panel. A Complex deformation observed at the middle of specimen behind loadcell, that signifying the effect of geometry and boundary condition with respect to hyperelestic behaviour of polyethylene. The computational procedure is recommended for mechanical analysis of polymer structures due to the capability of the model for accurate prediction of hyperelastic behaviour.

An Analysis of the Local Buckling Collapse Behavior of an Aluminum Square Tube under Concentrated Bending Moment Loads

2004 ◽  
Vol 261-263 ◽  
pp. 633-638 ◽  
Author(s):  
Sung Hyuk Lee ◽  
Nak Sam Choi
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Bending Moment ◽  
Bending Test ◽  
Aluminum Tube ◽  
Four Point Bending ◽  
Element Simulation ◽  
Steel Bars ◽  
Four Point Bending Test ◽  
Collapse Behavior

To analyze the bending collapse behavior of an aluminum square tube under the bending moment load, a finite element simulation for the four-point bending test has been performed. Using an aluminum tube beam specimen partly inserted with two steel bars, local buckling deformation near the center of the tube beam was induced. Simulated moment-rotation angle curve obtained during the post-collapse period of the aluminum tube with steel bars were in good agreement with experimental result, which was comparable to the result obtained from Kecman's theory. Using a combination of the four-point bending test and its finite-element simulation, analysis of the local buckling and the bending collapse behavior of an aluminum tube beam could be quantitatively accomplished.

scholarly journals Behaviour of flange joints in Steam Generator under thermal loads

2021 ◽  
Vol 309 ◽  
pp. 01082
Author(s):  
N. Rino Nelson
Keyword(s):  
Thermal Expansion ◽  
Contact Stress ◽  
Elevated Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Pressure Vessels ◽  
Thermal Loads ◽  
Internal Fluid ◽  
Linear Behaviour ◽  
Loading And Unloading ◽  
Differential Thermal Expansion

Pressure vessels such as steam generators are subjected to high temperature, in addition to high pressure during the operating condition. Flanges and bolts are made up of different materials whose coefficient of thermal expansion varies. Usually, thermal expansion in bolts is greater than that of flanges. At elevated temperatures bolts expand more than that of flanges, resulting in decrease of compression in connected members achieved during assembly stage, which in turn decreases the contact stress in gasket. This can lead to leakage of internal fluid. The loss in gasket contact stress due to differential thermal expansion can be nullified by using sleeves of higher thermal expansion between the flange-nut and flange-bolt head interfaces. At higher temperatures sleeves expand more than bolts and flanges, pushing the flanges closer towards each other, thus decreasing gap created due to differential thermal expansion. The behaviour of gasketed blind flange joint with and without sleeves is analysed and the performances are compared under thermal loads. The non-linear behaviour of gaskets is included by specifying the loading and unloading characteristics with hysteresis.

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