Assessment of Appropriate Pressure Vessel Flange Bolt - CORE

109 Pages·2004·2.46 MB·English

by  Brett C Taylor

University of Southern Queensland.
Faculty of Engineering and Surveying.

Assessment of Appropriate Pressure Vessel Flange Bolt
Tension by Finite Element Modelling.

A dissertation submitted by

Brett C Taylor

in fulfillment of the requirements of

Courses ENG4111 and ENG4112 Research Project

towards the degree of

Bachelor of Engineering (Mechanical)

Submitted: October 2004.
Abstract
Flanged joints on large diameter flanges can prove problematic to seal successfully with many
factors contributing to ensuring a successful operation. One such factor is stud bolt loading
contributing to stress and deflection of the flanged joint.

This investigation involves the use of finite element analysis (F.E.A) to predict levels of stress
and deflection of a particular flanged joint when the stud bolts are tightened and flange
pressurised. The level of stud bolt force selected must ensure the joint is sufficiently tight to
avoid leakage. However, the force must not be excessive causing damage.

The flanged joint is located on the channel head of a shell and tube heat exchanger.

For the purposes of this project, the educational version of ANSYS 5.5 was used thus a number
of critical assumptions were made to operate within the restrictions of the software.

As a comparative check of the F.E.A method, a conventional method termed the target load
bolt-up method was employed.

The analysis results using both methods, when interpreted, indicated the flange was not
excessively stressed. Field monitoring by observation of the flanged joint for signs of leakage
and other detrimental effects indicates the stud bolt load selected is acceptable.
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University of Southern Queensland.
Faculty of Engineering and Surveying.

. ENG4111 & ENG4112 Research Project .

Limitations of Use

The Council of the University of Southern Queensland, its Faculty of Engineering and
Surveying, and the staff of the University of Southern Queensland do not accept any
responsibility for the truth, accuracy or completeness of material contained within or associated
with this dissertation.

Persons using all or any part of this material do so at their own risk, and not at the risk of the
Council of the University of Southern Queensland, its Faculty of Engineering and Surveying, or
the staff of the University of Southern Queensland.

This dissertation reports an educational exercise and had no purpose or validity beyond this
exercise. The sole purpose of the course pair entitled ‘Research Project’ is to contribute to the
overall education within the student’s chosen degree program. This document, the associated
hardware, software, drawings, and other material set out in the associated appendices should not
be used for any other purpose: if they are so used, it is entirely at the risk of the user.

Prof G Baker
Dean
Faculty of Engineering and Surveying
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Certification

I certify that the ideas, designs and experimental work, results, analyses and conclusions set out
in this dissertation are entirely my own effort, except where otherwise indicated and
acknowledged.

I further certify that the work is original and has not been previously submitted for assessment
in any other course or institution, except where specifically stated.

Brett C Taylor
Student Number: Q29034680.

Signature:
Date:
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Acknowledgements

Thanks are expressed for the invaluable help and guidance received by my supervisors
Dr Wenyi Yan and Mr. Chris Snook of the University of Southern Queensland.

My wife and children also deserve thanks for enduring much inconvenience during the
construction of this dissertation.

I am also indebted to numerous colleagues at my place of employment who have provided
assistance, particularly Mr. Ross Barnard for his assistance in editing drawings and sketches.

Brett Taylor.
University of Southern Queensland.
October 2004.
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Table of Contents
Abstract........................................................................................................................................ii
Certification................................................................................................................................iv
Acknowledgements.....................................................................................................................v
Table of Contents.......................................................................................................................vi
List of Figures..............................................................................................................................x
List of Tables.............................................................................................................................xii
Nomenclature...........................................................................................................................xiii
Glossary....................................................................................................................................xxi
Chapter 1 Introduction...............................................................................................................1
1.1 Project Aims................................................................................................................1
1.2 Specific Objectives......................................................................................................2
1.3 Layout of Dissertation.................................................................................................2
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Chapter 2 Background...............................................................................................................5
2.1 General Description.....................................................................................................5
2.2 Heat Exchanger Details...............................................................................................7
2.3 Flanged Joint Data.....................................................................................................10
2.4 Gasket Data...............................................................................................................13
2.5 Discussion..................................................................................................................14
Chapter 3 Literature Review...................................................................................................17
3.1 Background................................................................................................................17
3.2 Taylor Forge Design Method....................................................................................18
3.3 EN 1591 European Method.......................................................................................20
3.4 Target Load Bolt-up Method.....................................................................................20
3.5 Finite Element Analysis Methods..............................................................................21
Chapter 4 F.E.A. Method of Design and Analysis.................................................................22
4.1 General Remarks.......................................................................................................22
4.2 Basic Assumptions....................................................................................................22
4.3 Modelling of Joint.....................................................................................................23
4.4 Material Properties....................................................................................................24
4.5 Dimensional Inputs....................................................................................................24
4.6 Model Elements.........................................................................................................28
4.7 Boundary Conditions and Meshing...........................................................................30
4.8 Loadings / Pressures..................................................................................................31
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Chapter 5 Target Load Bolt-up Method, Analysis and Results............................................36
5.1 General Remarks.......................................................................................................36
5.2 AS1210 Flange Design Bolt Forces..........................................................................37
5.3 Additional Allowances for Bolt-up...........................................................................38
5.4 Flange Moments........................................................................................................39
5.5 Flange Stresses..........................................................................................................41
5.6 Results of Analysis....................................................................................................44
5.7 Flange Rotation.........................................................................................................47
5.8 Stud Bolt Stresses......................................................................................................49
5.9 Summary of Results – Target Bolt-up Method..........................................................50
Chapter 6 Results of F.E.A. Analysis......................................................................................52
6.1 General Remarks.......................................................................................................52
6.2 Nodal Stress Results – Joint Assembly.....................................................................53
6.3 Nodal Stress Results – Flange...................................................................................55
6.4 Stress Results – Blind Flange....................................................................................58
6.5 Deflection Results.....................................................................................................60
6.6 Flange Rotation.........................................................................................................61
6.7 Summary of Results – F.E.A Method.........................................................................63

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Chapter 7 Conclusions and Recommendations......................................................................65
7.1 General Remarks.......................................................................................................65
7.2 Stress Results.............................................................................................................66
7.3 Deflection Results.....................................................................................................66
7.4 Field Trial Observations and Results.........................................................................67
7.5 Recommendations.....................................................................................................67

References..................................................................................................................................69
Appendix A Project Specification.................................................................................72
Appendix B Target Bolt-up Method Calculation Sheet Results................................74
Appendix C Selected Reference Data...........................................................................77
Appendix D AS2528 Bolting Data................................................................................82
Appendix E AS1210 Finite Element Guidance...........................................................84

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List of Figures
Figure 2.1 Heater Process Flow Diagram............................................................................5
Figure 2.2 General Arrangement of Heater..........................................................................7
Figure 2.3 Heat Exchanger Flange Assembly [View on Blind Flange]..............................8
Figure 2.4 Heat Exchanger Flange Assembly [View on Flange]........................................8
Figure 2.5 Detail of Flange Section...................................................................................10
Figure 2.6 Mating Blind Flange.........................................................................................11
Figure 2.7 Gasket Detail.....................................................................................................13
Figure 2.8 Typical Hydraulic Bolt Tensioner....................................................................14
Figure 4.1 Flange Details...................................................................................................24
Figure 4.2 Lines generated from Keypoints.......................................................................26
Figure 4.3 Areas generated from Lines..............................................................................27
Figure 4.4 Close-up view of Area Assembly.....................................................................27
Figure 4.5 Plane2 Element.................................................................................................28
Figure 4.6 Targe169 / Conta172 Elements.........................................................................29
Figure 4.7 Boundary Conditions and Meshing..................................................................30
Figure 4.8 Pressure Area....................................................................................................32
Figure 4.9 Illustration of Pressure Loads...........................................................................35
Figure 5.1 Bolt Load Comparative Range..........................................................................39
Figure 5.2 Typical Hubbed Flange Diagram......................................................................40
Figure 5.3 Longitudinal Hub Stress Region.......................................................................41
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