Analytical Modeling of Bolted Flange Joints With Full Face Gaskets

2004 ◽  
Author(s):  
Hichem Galai ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Contact Stress ◽  
Analytical Modeling ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Low Leakage ◽  
Proposed Model ◽  
Asme Code ◽  
The Many ◽  
Full Face ◽  
Bolted Flange

Following the low leakage performance of flat face flanges, neither Appendix 2 nor Appendix Y of the ASME code which describes the design rules of flanges, are reliable to assess load changes when full face gaskets are used. The prediction of the tightness of these connections relies very much on the level of precision of the gasket contact stress during operation. However, determining this stress is complex, due to the many geometric and material parameters involved. This paper analyses the behaviour of bolted joints with full face gaskets. It presents an analytical approach to evaluate the operating flange rotation, gasket load and contact stress that may be used for leak prediction. The method is based on the gasket-bolt-flange elastic interaction, including flange rotational flexibility. The proposed model is supported by comparison with numerical FEA of different size flanges.

Bolted Flange Joints With Full Face Gaskets: An Analytical Approach Based on Flexibility

2005 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Hichem Galai
Keyword(s):  
Analytical Approach ◽  
Design Method ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Low Leakage ◽  
Load Change ◽  
Proposed Model ◽  
Asme Code ◽  
Full Face ◽  
Bolted Flange

The low leakage performance of flanges with full face gaskets is attributed to the reliability of the design method used in Appendix 2 and Appendix Y of the ASME code in assessing accurately the bolt and gasket load changes. The prediction of tightness of these bolted joints relies very much on the level of precision of the gasket contact stress during operation. The evaluation of this stress requires a flexibility analysis of the joint including the flange the gasket and bolt and the interaction between them. This paper analyses the distribution of gasket stress and the load change in bolted joints with full face gaskets. It proposes a simple analytical approach capable of predicting flange rotation and bolt load change during operation. The method is based on the gasket-bolt-flange elastic interaction, including flange rotational flexibility. The proposed model is supported by comparison with numerical FEA of different size flanges.

A New Approach to Model Bolted Flange Joints With Full Face Gaskets

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Hichem Galai
Keyword(s):  
Elastic Interaction ◽  
Bolted Joints ◽  
Element Analysis ◽  
New Approach ◽  
Flexibility Analysis ◽  
Load Change ◽  
Proposed Model ◽  
Numerical Finite Element ◽  
Full Face ◽  
Bolted Flange

The poor leakage performance of flanges with full face gaskets is attributed to the low reliability of the existing design methods, and in particular, their lack of assessing accurately the bolt and gasket load changes. The prediction of tightness of bolted joints relies very much on the level of precision of the gasket contact stress during operation. The accurate evaluation of this stress requires a flexibility analysis of the joint that includes the flange, gasket, and bolts, and the interaction between them. This paper analyzes the distribution of gasket stress and the load change in bolted joints with full face gaskets. It proposes a simple analytical approach capable of predicting flange rotation and bolt load change during operation. The method is based on the gasket-bolt-flange elastic interaction, including flange rotational flexibility. The proposed model is supported by comparison with numerical finite element analysis of different size flanges.

Analytical Modeling of Flat Face Flanges With Metal-to-Metal Contact Beyond the Bolt Circle

2009 ◽  
Author(s):  
Hichem Galai ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Analytical Modeling ◽  
Plate Theory ◽  
Beam Theory ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Metal Contact ◽  
Design Rules ◽  
Load Change ◽  
Asme Code ◽  
Analytical Approaches

Design rules for flat face flanges with metal-to-metal contact beyond the bolt circle are covered by Appendix Y of the ASME Code. These design rules are based on Schneider’s work [1]. The prediction of tightness of these bolted joints relies very much on the level of precision of the O-ring gasket compression during operation. The evaluation of this compression requires a rigorous flexibility analysis of the joint including bolt-flange elastic interaction. This paper analyses flange separation and the bolt load change in flat face bolted joints. It proposes two different analytical approaches capable of predicting flange rotation and bolt load change during operation. The first method is based on beam theory applied to a continuous flange sector. This approach is an improvement of the discrete beam theory used by Schneider [1]. The second method is based on circular plate theory and is developed for the purpose of a more accurate assessment of the load changes. As in the Taylor Forge method, this approach is in general better suited than the beam theory for flat face flanges in particular when the flange width is small. The proposed models are compared to the discrete beam theory and validated using numerical FEA on different flange sizes.

Analytical Modeling of the Contact Stress With Nonlinear Gaskets

2001 ◽  
Vol 124 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Michel Derenne
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Room Temperature ◽  
Analytical Modeling ◽  
Design Rules ◽  
Nonlinear Mechanical ◽  
Leak Tightness ◽  
Gasket Material ◽  
Bolted Flange ◽  
Contact Stress Distribution

Gasket contact stress and its variation through the gasket width is caused by the rotation of the flange and has an influence on the leakage tightness behavior of bolted flange joints. The future implementation by the ASME of proposed design rules is based on new gasket constants obtained from the ROTT (room temperature tightness) tests conducted on rigid platens. The gasket contact stress distribution needs to be addressed for the purpose of better joint tightness predictions. This paper presents a comprehensive analytical method that predicts the gasket contact stress distribution taking into account the nonlinear mechanical behavior of the gasket material. Based on the flange rotational flexibility, the proposed analytical model that is implemented in the “SuperFlange” program is supported and validated by numerical FEA and experimental analyses on flange rotations, radial distribution of gasket contact stress, and joint leak tightness.

A Novel Formulation of Elastic Interaction in Gasketed Bolted Joints

2007 ◽  
Author(s):  
Ali A. Alkelani ◽  
Sayed A. Nassar ◽  
Basil A. Housari
Keyword(s):  
Mathematical Model ◽  
Load Distribution ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Good Prediction ◽  
Proposed Model ◽  
Joint Tightening ◽  
The Mathematical Model ◽  
Bolt Spacing ◽  
Initial Assembly

A novel mathematical model is proposed for studying elastic interaction in gasketed bolted joints. The model predicts the tension changes in tightened bolts due to the subsequent tightening of other bolts in the joint. It also predicts the final clamp load distribution after the completion of joint tightening. The model is used to investigate the effect of various factors on the elastic interaction phenomenon; factors include the gasket thickness, bolt spacing, fastener preload level, and the tightening sequence of various bolts. Experimental verification is provided for the validation of the mathematical model. Experimental and analytical results are presented and discussed. The proposed model provides good prediction of the final clamp load in the joint. Moreover, the proposed model may be used to determine the level of initial bolt tension in each bolt that would be necessary to achieve the desired level of uniform clamp load in the joint at initial assembly.

Analytical Modeling of a Bolted Flange Joint Subjected to Creep Relaxation

2004 ◽  
Author(s):  
Akli Nechache ◽  
Abdel-Hakim Bouzid ◽  
Van Ngan Leˆ
Keyword(s):  
Experimental Data ◽  
Analytical Modeling ◽  
Nuclear Reactors ◽  
Weak Link ◽  
Flange Joint ◽  
Load Relaxation ◽  
Controlling Parameter ◽  
Asme Code ◽  
Subsequent Loss ◽  
Bolted Flange

Bolted flanged gasketed joints are the weak link between pressure vessel equipments including nuclear reactors. Their leakage tightness behavior is compromised due to the effect of creep of the gasket, the bolts and the flange, which relaxes the bolt load and causes a subsequent loss of the gasket contact stress. This is especially true when the joint is operating under high pressure and high temperature conditions. Apart from an acknowledgement of this affect, the ASME code does not give specific guidelines to help the design engineer in assessing this effect. The objective of this paper is to present an analytical method capable of predicting the bolt load relaxation in a gasketed joint as a result of creep of either the gasket, the bolt and the flange separately or all together. The proposed method is validated by comparison with 3D FE models of different size flanges and experimental data. A strong emphasis will be put on flange rigidity, which is the major controlling parameter of the load relaxation.

An Analytical Solution for Evaluating Gasket Stress Change in Bolted Flange Connections Subjected to High Temperature Loading

2005 ◽  
Vol 127 (4) ◽  
pp. 414-422 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Akli Nechache
Keyword(s):  
Elevated Temperature ◽  
Operating Temperature ◽  
Interaction Model ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Analytical Models ◽  
Cover Plate ◽  
Thermally Induced ◽  
Internal Fluid ◽  
Bolted Flange

The tightness of bolted flanged joints subjected to elevated temperature is not properly addressed by flange design codes. The development of an analytical method based on the flexibility of the different joint components and their elastic interaction could serve as a powerful tool for elevated temperature flange designs. This paper addresses the effect of the internal fluid operating temperature on the variation of the bolt load and consequently on the gasket stress in bolted joints. The theoretical analysis used to predict the gasket load variation as a result of unequal radial and axial thermal expansion of the joint elements is outlined. It details the analytical basis of the elastic interaction model and the thermally induced deflections that are used to evaluate the load changes. Two flange joint type configurations are treated: a joint with identical pair of flanges and a joint with a cover plate. The analytical models are validated and verified by comparison to finite element results.

Numerical Simulation of the Assembly Process of Bolted Flange Joints Used in Rotating Machinery

2020 ◽  
Author(s):  
Linbo Zhu ◽  
Abdel-Hakim Bouzid ◽  
Jun Hong ◽  
Zhenming Shi
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Elastic Interaction ◽  
Rotating Machinery ◽  
Least Square ◽  
Bolted Joints ◽  
Fe Method ◽  
Element Analysis ◽  
Bolt Preload ◽  
Bolted Flange

Abstract Bolted joints are widely used to connect structural components in rotating machinery. However, the initial tightening of the bolts is a delicate operation because it is extremely difficult to achieve the target load and uniformity due to elastic interaction. The scatter in the bolt preload has a major impact on the concentricity and consequently the dynamic behavior of rotating machinery. The risk of failure due to vibration and fatigue under service loading becomes an issue. This paper treats the effect of elastic interaction on the eccentricity during the tightening of bolted joints of rotating machinery using finite element (FE) method. In this regard, a two-component bolted flange joint of a high pressure compressor (HPC) of an aero-engine is investigated. The component surface tolerances measured by Rotary Precision Instruments (RPI) are taken into account in the numerical simulation. A method is proposed to calculate the concentricity of components obtained from the radial runout data based on the Least Square method (LSM). The scatter in bolt preload under different interference fit, surfaces tolerance, initial preload, and tightening sequence are evaluated. Furthermore, the influence of these structures and tightening sequence parameters on the concentricity are investigated. The validity of the finite element analysis is supported by experimental tests conducted on scaled specimens of HPC. This study can provide guidance and enhance the dynamic performance of bolted joints for rotating machinery.

Formulation of Elastic Interaction Between Bolts During the Tightening of Flat-Face Gasketed Joints

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Ali A. Alkelani ◽  
Sayed A. Nassar ◽  
Basil A. Housari
Keyword(s):  
Mathematical Model ◽  
Load Distribution ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Good Prediction ◽  
Proposed Model ◽  
Joint Tightening ◽  
The Mathematical Model ◽  
Bolt Spacing ◽  
Initial Assembly

A novel mathematical model is proposed for studying elastic interaction in gasketed bolted joints. The model predicts the tension changes in tightened bolts due to the subsequent tightening of other bolts in the joint. It also predicts the final clamp load distribution after the completion of joint tightening. The model is used to investigate the effect of various factors on the elastic interaction phenomenon; factors include the gasket thickness, bolt spacing, fastener preload level, and tightening sequence of various bolts. Experimental verification is provided for the validation of the mathematical model. Experimental and analytical results are presented and discussed. The proposed model provides a good prediction of the final clamp load in the joint. Moreover, the proposed model may be used to determine the level of initial bolt tension in each bolt that would be necessary to achieve the desired level of uniform clamp load in the joint at the initial assembly.

Application of Bolted Flange Joint Assembly Guidelines HPIS Z103 TR to ePTFE Sheet Gasket

2008 ◽  
Author(s):  
Hirokazu Tsuji ◽  
Yuuki Terui
Keyword(s):  
Relaxation Rate ◽  
Modulus Of Elasticity ◽  
Elastic Interaction ◽  
Flange Joint ◽  
Fiber Sheet ◽  
Force Reduction ◽  
Assembly Procedure ◽  
Bolted Flange ◽  
Application Scope ◽  
Joint Assembly

Bolt tightening guidelines HPIS Z 103 TR for flange joint assemblies have been developed to provide a simple and effective procedure to tighten flange joint bolts. This assembly procedure is applicable to compressed fiber sheet gaskets and spiral wound gaskets, but is not applicable to expanded PTFE (ePTFE) sheet gaskets for the reason that the ePTFE material has lower modulus of elasticity and higher creep/relaxation rate. In this study, expansion of the application scope of HPIS Z103 TR to ePTFE sheet gaskets is investigated. Tightening tests are conducted using flange joint specimens of JPI 4 inch and 6 inch, and all bolt forces and flange gaps are measured at each tightening step to check for uneven tightening. Uniformity of the bolt forces and flange gaps are comparable to those obtained by other types of gaskets or by tightening procedure ASME PCC-1. The influences of gasket relaxation and elastic interaction on the bolt forces are also demonstrated. As a result, flange joint assembly guidelines HPIS Z 103 TR can be considered applicable to the high-density ePTFE sheet gasket, although a post-tightening step of 1 or 2 passes is necessary to compensate for the bolt force reduction induced by gasket relaxation.

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