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

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Hichem Galai ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Plate Theory ◽  
Beam Theory ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Metal Contact ◽  
Element Analysis ◽  
Design Rules ◽  
Load Change ◽  
American Society ◽  
Analytical Approaches

Design rules for flat face flanges with metal-to-metal contact beyond the bolt circle are covered by Appendix Y of the American Society of Mechanical Engineers Code. These design rules are based on Schneider’s work (1968, “Flat Faces Flanges With Metal-to-Metal Contact Beyond the Bolt Circle,” ASME J. Eng. Power, 90(1), pp. 82–88). The prediction of tightness of these bolted joints relies very much on the level of precision of the self-sealing 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 the beam theory applied to a continuous flange sector. This approach is an improvement of the discrete beam theory used in the Schneider model. The second method is based on the 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 with the discrete beam theory and validated using numerical finite element analysis on different flange sizes.

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.

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.

A New Tightening Methodology for Gasketed Joints Based on Nonlinear Finite Element Analysis

2008 ◽  
Author(s):  
Sayed A. Nassar ◽  
Zhijun Wu ◽  
Xianjie Yang
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Elastic Interaction ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Bolted Joints ◽  
Model Parameters ◽  
Element Analysis ◽  
Loading And Unloading ◽  
Nonlinear Finite Element Model

A three dimensional nonlinear finite element model is developed for achieving a uniform clamp load in gasketed bolted joints. The model is used for both multiple and single pass tightening patterns. Geometric nonlinearity of the gasket is taken into account and plastic model parameters are experimentally determined. The effect of the tightening pattern, gasket loading and unloading history, and the preload level is investigated. The validity of the FEA methodology is experimentally verified. This study helps improve the reliability of gasketed bolted joints by minimizing the bolt-to-bolt clamp load variation caused by elastic interaction among the various bolts in the joint during initial joint bolt-up.

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.

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.

Natural frequency analysis of a functionally graded rotor-bearing system with a slant crack subjected to thermal gradients

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Arnab Bose ◽  
Prabhakar Sathujoda ◽  
Giacomo Canale
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Power Law ◽  
Beam Theory ◽  
Functionally Graded ◽  
Thermal Gradients ◽  
Element Analysis ◽  
Rotor Bearing ◽  
Natural Frequency Analysis ◽  
Bearing System

Abstract The present work aims to analyze the natural and whirl frequencies of a slant-cracked functionally graded rotor-bearing system using finite element analysis for the flexural vibrations. The functionally graded shaft is modelled using two nodded beam elements formulated using the Timoshenko beam theory. The flexibility matrix of a slant-cracked functionally graded shaft element has been derived using fracture mechanics concepts, which is further used to develop the stiffness matrix of a cracked element. Material properties are temperature and position-dependent and graded in a radial direction following power-law gradation. A Python code has been developed to carry out the complete finite element analysis to determine the Eigenvalues and Eigenvectors of a slant-cracked rotor subjected to different thermal gradients. The analysis investigates and further reveals significant effect of the power-law index and thermal gradients on the local flexibility coefficients of slant-cracked element and whirl natural frequencies of the cracked functionally graded rotor system.

Delamination of Laminate Plates

2014 ◽  
Vol 969 ◽  
pp. 97-100 ◽  
Author(s):  
Eva Kormaníková
Keyword(s):  
Finite Element Analysis ◽  
Mixed Mode ◽  
Plate Theory ◽  
Laminate Plate ◽  
Element Analysis ◽  
Interface Elements ◽  
First Order ◽  
Plate Elements ◽  
Interface Modeling ◽  
Shear Deformable

The paper deals with numerical modeling of delamination of laminate plate consists of unidirectional fiber reinforced layers. The methodology adopts the first-order shear laminate plate theory and fracture and contact mechanics. There are described sublaminate modeling and delamination modeling by the help of finite element analysis. With the interface modeling there is calculated the energy release rate along the lamination front. Numerical results are given for mixed mode delamination problems by implementing the method in a 2D finite analysis, which utilizes shear deformable plate elements and interface elements. Numerical example is done by the commercial ANSYS code.

scholarly journals Dynamic Analysis of Honeycomb Sandwich Beam with Multiple Debonds

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
B. Saraswathy ◽  
R. Ramesh Kumar ◽  
Lalu Mangal
Keyword(s):  
Analytical Solution ◽  
Transient Analysis ◽  
Sandwich Beam ◽  
Beam Theory ◽  
Beam Length ◽  
Honeycomb Core ◽  
Element Analysis ◽  
Fast Fourier Transform Analysis ◽  
Honeycomb Sandwich ◽  
Nonlinear Transient

Analytical formulation for the evaluation of frequency of CFRP sandwich beam with debond, following the split beam theory, generally underestimates the stiffness, as the contact between the honeycomb core and the skin during vibration is not considered in the region of debond. The validation of the present analytical solution for multiple-debond size is established through 3D finite element analysis, wherein geometry of honeycomb core is modeled as it is, with contact element introduced in the debond region. Nonlinear transient analysis is followed by fast Fourier transform analysis to obtain the frequency response functions. Frequencies are obtained for two types of model having single debond and double debond, at different spacing between them, with debond size up to 40% of beam length. The analytical solution is validated for a debond length of 15% of the beam length, and with the presence of two debonds of same size, the reduction in frequency with respect to that of an intact beam is the same as that of a single-debond case, when the debonds are well separated by three times the size of debond. It is also observed that a single long debond can result in significant reduction in the frequencies of the beam than multiple debond of comparable length.

Fracture Mechanics of Thin Plates and Shells Under Combined Membrane, Bending, and Twisting Loads

2005 ◽  
Vol 58 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Alan T. Zehnder ◽  
Mark J. Viz
Keyword(s):  
Fracture Mechanics ◽  
Plate Theory ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Crack Tip ◽  
Thin Plates ◽  
Element Analysis ◽  
Crack Tip Fields ◽  
Plates And Shells ◽  
Membrane Bending

The fracture mechanics of plates and shells under membrane, bending, twisting, and shearing loads are reviewed, starting with the crack tip fields for plane stress, Kirchhoff, and Reissner theories. The energy release rate for each of these theories is calculated and is used to determine the relation between the Kirchhoff and Reissner theories for thin plates. For thicker plates, this relationship is explored using three-dimensional finite element analysis. The validity of the application of two-dimensional (plate theory) solutions to actual three-dimensional objects is analyzed and discussed. Crack tip fields in plates undergoing large deflection are analyzed using von Ka´rma´n theory. Solutions for cracked shells are discussed as well. A number of computational methods for determining stress intensity factors in plates and shells are discussed. Applications of these computational approaches to aircraft structures are examined. The relatively few experimental studies of fracture in plates under bending and twisting loads are also reviewed. There are 101 references cited in this article.

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