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

2016 ◽  
Vol 230 (6) ◽  
pp. 464-473 ◽  
Author(s):  
N Rino Nelson ◽  
N Siva Prasad ◽  
AS Sekhar
Keyword(s):  
Elevated Temperature ◽  
Internal Pressure ◽  
Contact Stress ◽  
Thermal Loading ◽  
Elevated Temperatures ◽  
Flange Joint ◽  
Temperature Dependent ◽  
Surface Rotation ◽  
Bolt Preload ◽  
Seating Surface

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.

The Sealing Performance Evaluation of Bolted Flexible Box-Shaped Flange Joints Under Thermal Conduction Conditions

2009 ◽  
Author(s):  
Ryou Kurosawa ◽  
Toshiyuki Sawa ◽  
Yuya Omiya ◽  
Kentaro Tenma
Keyword(s):  
Elevated Temperature ◽  
Internal Pressure ◽  
Thermal Conduction ◽  
Stress Distributions ◽  
Flange Joint ◽  
The Finite Element Method ◽  
Gas Leakage ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Helium Gas

Bolted joints with gaskets such as flexible box-shaped flange joints have been used in mechanical structures. The joints 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 joint with gaskets, it is important to evaluate the sealing performance of the joints under internal pressure and thermal conduction conditions. In this paper, the contact gasket stress distributions and changes in bolt load in the bolted flexible box-shaped flange joint with joint 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 joint sheet gasket. Using the contact gasket stress distributions under internal pressure at an elevated temperature (Helium gas) obtained from the FEM calculations and the amount of the gas leakage measured in the experiment, the sealing performances are evaluated experimentally and numerically. In addition, the effect of the thermal conduction condition on the sealing performance is examined. Furthermore, a method how to determine the bolt preload of the flexible box-shaped flange joint at an elevated temperature for a given tightness parameter is demonstrated. Discussion is made on the sealing performance.

FEM Stress Analysis of Bolted Flange Joints in Elevated Temperature Service Condition

2018 ◽  
Author(s):  
Lu Wang ◽  
Xuedong Chen ◽  
Zhichao Fan ◽  
Jilin Xue
Keyword(s):  
Steady State ◽  
Elevated Temperature ◽  
Internal Pressure ◽  
Heating Rate ◽  
Contact Stress ◽  
Thermal Loading ◽  
Structural Integrity ◽  
Bolt Stress ◽  
Transient Thermal ◽  
Bolted Flange

Performance of a bolted flange joint (BFJ) is characterized mainly by its ‘strength’ and ‘sealing capability’. How to keep the ‘strength’ and ‘sealing capability’ for the BFJ serving at elevated temperature is a difficult problem in engineering applications. The variations of bolt stress and gasket contact stress play an important role on the structural integrity and sealing performance of BFJ in the bolt-up, pressurization and heat-up stages. In this paper, a three-dimensional elastic-plastic finite element model has been developed to investigate the performance of joint under combined internal pressure and elevated temperature. The thermal-structural coupling method has been used to analyze the variations of axial bolt force, maximum blot stress and gasket contact stress under steady-state and transient thermal loadings. The effects of internal pressure, temperature as well as the heating rate on the variations of bolt load, bolt stress and gasket contact stress have been evaluated. The results show that the maximum bolt stress increases while average gasket contact stress decreases with increasing the temperature under steady-state thermal loading. Besides, when the transient thermal loading is considered, heating rate has a significant effect on the maximum bolt stress and gasket contact stress. This research will contribute to the design of BFJ subjected to elevated temperature.

Finite Element Analysis of a Gasketed Flange Joint Under Combined Internal Pressure and Thermal Transient Loading

2007 ◽  
Author(s):  
Muhammad Abid ◽  
Javed A. Chattha ◽  
Kamran A. Khan
Keyword(s):  
Finite Element Analysis ◽  
Steady State ◽  
Internal Pressure ◽  
Thermal Loading ◽  
Flange Joint ◽  
Element Analysis ◽  
Transient Loading ◽  
Thermal Transient ◽  
Transient Thermal ◽  
Bolted Flange

Performance of a bolted flange joint is characterized mainly by its ‘strength’ and ‘sealing capability’. A number of analytical and experimental studies have been conducted to study these characteristics only under internal pressure loading. In the available published work, thermal behavior of the pipe flange joints is discussed under steady state loading with and without internal pressure and under transient loading condition without internal pressure. The present design codes also do not address the effects of steady state and thermal transient loading on the structural integrity and sealing ability. It is realized that due to the ignorance of any applied transient thermal loading, the optimized performance of the bolted flange joint can not be achieved. In this paper, in order to investigate gasketed joint’s performance i.e. joint strength and sealing capability under combined internal pressure and transient thermal loading, an extensive nonlinear finite element analysis is carried out and its behavior is discussed.

Elasto-Plastic FEM Stress Analysis of Pipe Flange Connections Under Internal Pressure

2006 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Satoshi Nagata ◽  
Naofumi Ogata
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Contact Stress ◽  
Strain Curve ◽  
Stress Distributions ◽  
Element Analysis ◽  
Nominal Diameter ◽  
Bolt Preload ◽  
Spiral Wound

This paper deals with the stress analysis of a pipe flange connection with a spiral wound gasket using the elasto-plastic finite element method taking account the hysteresis and the non-linearity in the stress-strain curve of the spiral wound gasket, when an internal pressure is applied to the pipe flange connections with the different nominal diameters from 2 to 20. The effects of the nominal diameter of the pipe flange on the contact stress distributions at the interfaces are examined. Leakage tests of the pipe flange connections with 3 and 20 nominal diameters were conducted and measurement of the axial bolt force was also performed. The results by the finite element analysis are fairly consistent with the experimental results concerning the variation in the axial bolt force. By using the contact stress distributions and the results of the leakage test, the new gasket constants are evaluated. As a result, it is found that the variations in the contact stress distributions are substantial due to the flange rotation in the pipe flange connections with the larger nominal diameter. In addition, a method to determine the bolt preload for a given tightness parameter is demonstrated.

FEM Stress Analysis and Sealing Performance in Bolted Flange Connections With Cover of Pressure Vessel Subjected to Internal Pressure

2003 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Rie Higuchi
Keyword(s):  
Internal Pressure ◽  
Contact Stress ◽  
Pressure Vessel ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Bolted Flange ◽  
Contact Stress Distribution ◽  
Spiral Wound

The stresses of a bolted flange connection with a cover of pressure vessel (CPV) in which a spiral wound gasket is inserted, under internal pressure are analyzed taking account a hysteresis of the gasket by using the finite element method (FEM). The leakage tests were also conducted using an actual bolted flange connection with a CPV with a spiral wound gasket. Using the contact stress distribution of the bolted flange connection with a CPV under internal pressure and the tightness parameter, the values of the new gasket constants were obtained by taking into account the changes in the contact stress. A difference in the new gasket constants between the estimated values obtained from the actual bolted flange connection with a CPV and the values obtained by the PVRC procedure was small. In addition, a method to determine the bolt preload for a given tightness parameter was demonstrated. The obtained results of the bolt preload for the bolted flange connection with a CPV were in a fairly good agreement with those obtained by the PVRC procedure under a lower pressure application. However, a difference in the bolt preload was about 7% when the internal pressure was increased.

Critical Load Analysis of Double-Hinged Circular Steel Arch In-Plane under High Temperature of Fire

2011 ◽  
Vol 243-249 ◽  
pp. 3-6 ◽  
Author(s):  
Yu Lai Han ◽  
Bai Tao Sun ◽  
Zhu Ju ◽  
Yong Gang Wang
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Critical Load ◽  
Thermal Loading ◽  
Elevated Temperatures ◽  
Structural Response ◽  
Steel Material ◽  
The Stability ◽  
Variation Trends ◽  
Significant Factors

This paper addresses the stability behaviour in-plane and the critical load of the double-hinged circular steel arch when subjected to elevated temperature caused by fire, the study is restricted to the thermoelastic structural response of the steel material and therefore the high-temperature effects of yielding are not considered. In order to model structural response of the steel arch under thermal loading, some significant factors such as the degradation of the stiffness of the steel arch prior to yielding at elevated temperatures is taken into account, the formulation of critical load is proposed and their variation trends with temperatures is analysed. The proposed method has significant potential for use in the analysis of steel arches subjected to uniformly distributed load at elevated temperature and can provide a foundation for codified procedures in design.

Behavior of Flange Joints Under Combined Internal Pressure and Thermal Loading: The Case of Using Metal-to-Metal Contact Type Gaskets

2013 ◽  
Author(s):  
Kai Ma ◽  
Yi Zhang ◽  
Lanzhu Zhang ◽  
Kaishu Guan
Keyword(s):  
Internal Pressure ◽  
Nuclear Power ◽  
Thermal Loading ◽  
Three Dimensional ◽  
Element Model ◽  
Metal Contact ◽  
Flange Joint ◽  
Contact Type ◽  
Bolted Flange ◽  
Nonlinear Finite Element Model

In a bolted flange joint, metal-to-metal contact type gasket takes over only part of the bolt load to achieve seating stress, and the additional bolt load is transmitted to the metal-to-metal contact to compensate for the unloading effects due to internal and external loadings. Due to this advantage, flange joints with metal-to-metal contact type gaskets are gradually used in chemical industry, nuclear power industry, etc. A three-dimensional nonlinear finite element model is developed to highlight the complex behavior of the flange joint with metal-to-metal contact type gasket under combined internal pressure and thermal loading. Despite of the common perception that the gasket stress in the metal-to-metal contact type gasket stays constant, reduced gasket stress is concluded due to flange rotation and joint thermal expansion.

Sealing Performance Evaluation of Pipe Flange Connection Under Elevated Temperatures

2007 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yoshio Takagi ◽  
Hiroyasu Torii
Keyword(s):  
Elevated Temperature ◽  
Stress Distribution ◽  
Internal Pressure ◽  
Elevated Temperatures ◽  
Flange Connection ◽  
Gas Leakage ◽  
Sealing Performance ◽  
Nominal Size ◽  
Operational Temperature ◽  
Contact Stress Distribution

Since a lot of pipe flange connections are exposed to elevated temperature during operation, it is important to evaluate the sealing performance of the connections under operational temperature. In this study, the sealing performance of pipe flange connection was experimentally evaluated by measuring the amount of gas leakage at room temperature (RT), 100 °C and 200 °C in addition to internal pressure. Non-asbestos graphite gaskets were used in the experiment. The nominal size of the pipe flange used during the experimental study was 3 inch. The eight bolts and nuts were tightened according to ASME PCC-1 and the Japanese method (HPIS). During assembly, the axial bolt force was individually measured with strain gauges attached to each bolt. The scatter in the axial bolt force during the assembling process was examined and compared between the ASME and the HPIS. In addition, the gasket contact stress distribution of each assembly process was calculated by finite element method under elevated temperature and internal pressure. In the FE study, experimentally measured physical properties such as elastic modulus and thermal expansion were used. ηhe amount of leakage was estimated from the contact gasket stress distribution obtained by FE analysis. The estimated axial bolt forces were compared with those of experimental ones.

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