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TRANSVERSE VIBRATIONS
OF BELLO\VS EXPANSION JOINTS
by
VAIDUTIS FELIKSAS JAKUBAUSKAS, B.Sc., M.Sc., M. Eng.
A Thesis
Submitted to the School of Graduate Studies
In Partial Fulfillment of the Requirements
For the Degree
Doctor of Philosophy
McMaster University
(c) Copyright by Vaidutis Feliksas Jakubauskas, June 1995
TRANSVERSE VIBRATIONS
OF BELLO\VS EXPANSION JOINTS
DOCTOR OF PHILOSOPHY (1995) (Mechanical Engineering)
TITLE:
McMaster University Hamilton. Ontario
Investigations of Transverse Vibrations of Bellows Expansion Joints
AUTHOR: Vaidutis Feliksas Jak"Ubauskas,
B.Sc. (Kaunas Politechnical Institute, Lithuania)
M.Sc. (Odessa Civil Engineering Institute, Ukraine)
M.Eng. ( McMaster University, Canada)
SUPERVISOR: Professor D.S. Weaver
NUMBER OF PAGES: xv, 245
II
ABSTRACl
Bellows expansion joints are used in piping systtms to absorb significant axial
and/or transverse motions. Unfortunately, their flexibility also makes them susceptible to
vibration. This thesis presents a detailed analysis of the transverse vibrations of single and
double bellows expansion joints, including the effects of internal fluid.
A differential equation of motion is developed which treats transverse bellows
vibrations including the effects of fluid added mass, rotary inertia and internal pressure.
The added mass is determined from potential flow theory and provided in the form of a
mode dependent added mass coefficient. The equation of motion is solved for the first four
transverse modes and comparison with experiments shows excellent agreement. The
neglect of rotary inertia and the effect of convolution distortion on fluid added mass in the
EJMA Standard makes the latter's preC:ictions for natural frequency significantly higher
than those measured , especially for transverse modes above the fundamental.
The equation of motion is also solved approximately to provide an analytical
expression for transverse natural frequencies. The results are presenteC: in a form which
makes hand calcuiations possible for the first four modes of single and double bellows
expansion joints. Experiments in still fluid as well as flow-induced motion show excellent
agreement with predicted frequencies.
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ACKNOWLEDGEMENTS
I would like to express my sincere gratitude to my supervisor Dr. D.S. Weaver for
suggesting the problem. His constant encouragement and advice, often extending beyond
the s~ope of this work, are greatly appreciated.
I am grateful to the late Dr. F.A. Mirza for the use of his computer software.
I also am grateful to Dr. M.A. Dokainish for making it possible to use his
computing facility.
I am thankful for the assistance offered by Mr. L.Baksys in the preparation of
drawings and the final copy of the manuscript.
I acknowledge the financial support of the Natural Sciences and Engineering Re-
search Council of Canada.
Lastly, I would like to thank my parents for their unending support and encourage-
ment.
IV
TABLE OF CONTENTS
Page CHAPTERl INTRODUCTION 1
CHAPTER2 REVIEW OF INVESTIGATIONS 7 OF TRANSVERSE VIBRATIONS IN CORRUGATED PIPE EXPANSION JOINTS
2.1 General Information about Flow- 7 Induced Vibrations
2.2 The Survey of Flow Induced Vibrations 10 of Corrugated Pipe Expansion Joints
2.3 The Survey oflnvestigations 15 of Axial Stiffness of Bellows
2.4 Investigations of Axial 19 Vibrations in Bellows
2.5 The Survey of Investigations of Transverse Vibrations 29 of Corrugated Pipe Expansion Joints
CHAPTER3 STIFFNESS AND INERTIAL PROPERTIES 35 IN CASE OF TRANSVERSE VIBRATION OF BELLOWS
3.1 The Bending Stiffhess of Bellows 35 3.2 Bellows as a Shell of Revolution 37 3.3 Bellows as a Solid of Revolution 42 3.4 Peculiarities and Comparison of 47
Results of Calculation of Axial Stiffness of Bellows 3.5 Bellows Mass 50 3.6 Additional Fluid Mass of Bellows 51 3.7 FE Formulation of Laplace Equation 58
in 30 Domain with Mixed Boundary Conditions 3.o Added Fluid Mass, i. 70 3.9 Second Moment oflnertia of 75
Cross-section of Bellows 3.10 Mass Moment of Inertia of Connecting 78
Pipe of Universal Expansion Joint
CHAPTER4 ASSUMPTIONS AND DIFFERENTIAL EQUATION 81 OF TRANSVERSE VIBRATION OF BELLOWS
4.1 The Modes ofNatural Transverse 81 4.2 The Influence of Shear and Inertia 84
of Rotation of Cross-section on Vibrating Bellows
v
4.3 The Influence of Coriolis Forces 89 on Natural Vibrations of Bellows
4.4 The Influence oflnside Pressure and the Centrifugal 97 Force of the Flow on Transverse Vibration of Bellows
4.5 Assumptions and Derivation of Differential Equation of 104 Transverse Vibration of Bellows Using Newtonian Approach
CHAPTERS THEORETICAL INVESTIGATION OF NATURAL 107 TRANSVERSE VIBRATIONS OF SINGLE BELLO\VS EXPANSION JOINT
5.1 Solution of Differential Equation 107 5.2 Single Bellows Type Expansion Joint I I 1
Natural Frequencies 5.3 The Exact Solution of Single Bellows Expansion 114
Joint Natural Frequencies and its Comparison with Rayleigh Quotient Solution
5.4 Instability condition for Single 1 I 7 Bellows expansion Jo:nt
CHAPTER6 THEORETICAL INVESTIGATION OF I 19 NATURAL VIBRATIONS OF UNIVERSAL EXPANSION JOINT LATERAL MODE
6.1 Derivation of Boundary Conditions for Vibration I 19 of Universal Expansion Joint in Lateral Mode
6.2 Solution of Differential equation 122 6.3 Solution of Bernoulli-Euler eq1iation 125 6.4 General Expression for Universal 129
Expansion Joint Lateral Modes Natural Frequencies 6.5 First Lateral Mode Natural Frequency 130
of Universal Expansion Joint without Lateral Supports 6.6 Second and Third Lateral Modes Natural Frequencies 136
of Universal Expansion Joint without Lateral Supports 6.7 First Lateral Mode Natural Frequency 140
of Universal Expansion Joint with Lateral Supports 6.8 The Exact Solution of Universal Expansion Joint 145
Lateral Mode Natural Frequency and Its Comparison with the Rayleigh Quotient Solution
6.9 Instability Condition for Universal 150 Expansion Joint Lateral Mode
CHAPTER 7 THEORETICAL INVESTIGATION OF I 5 I NATURAL VIBRATIONS OF UNIVERSAL EXPANSION JOINT ROCKING MODE
7.1 Derivation of Boundary Conditions for Vibration 151 of Universal Expansion Joint Rocking Mode
VI
7.2 Derivation of Differential Equation 155 and Boundary Conditions Using Hamilton's Principle
7.3 Solution of Differential Equation 160 7.4 Solution of Bernoulli-Euler Equation 163 7.5 General Expression for Universal Expansion Joint 168
Rocking Modes Natural Frequencies 7.6 First Rocking Mode Natural Frequency 169
of Universal Expansion Joint without Lateral Supports 7.7 Second and Third Rocking Mode Natural Frequency 177
of Universal Expansion Joint without Lateral Supports 7.8 First Rocking Mode Natural Frequency 180
of Universal Epansion Joint with Lateral Supports 7.9 The Exact Solution of Universal Expansion Joint 186
Rocking Mode Natural Frequency and Its Comparison with Rayleigh Quotient Solution
7.10 Instability Condition for Universal 191 Expansion Joint Rocking Mode
CHAPTERS EXPERil\IENTAL INVESTIGATION OF NATURAL 193 TRANSVERSE VIBRATIONS OF BELLO\VS
8.1 Apparatus for Investigation of Natural Transverse 193 Vibrations of Fixed-Fixed Bellows
8.2 The Method and Results of Experimental Investigation 197 of Natural Vibrations of Bellows Expansion Joint
CHAPTER9 EXPERIMENTAL INVESTIGATION OF FLOW- 216 INDUCED TRANSVERSE VIBRATIONS OF BELLOWS EXPANSION JOINTS
9.1 General Information about Water/Wind Tunnels 216 9.2 Water Tunnel Design 220 9.3 Experimental Results 222
CHAPTER 10 CONCLUSIONS 236
REFERENCES 240
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LIST OF FIGURES
Figure Page
2.1 The Geometry of bellows 11
2.2 Various types of expansion joints 12
2.3 The kinds of bellows vibration modes 13
2.4 Cr for convoluted bellows, EJMA Std. (1980) 17
2.5 Finite element discretisation of bellows and fluid domains 24
2.6 Bellows added mass coeffi~ient and bellows 26 frequency f (Hz) as functions of mode number for five convolution bellows, Jakubauskas and Weaver ( 1992)
2.7 First six axisym netric modes of five 27 convolution bellows, Jakubauskas and Weaver (1992)
2.8 Installation P.xamplt:s of bellows 31
3.1 Two node 6 DOF axisymmetric element 38
3.2 Half-convolution domain for shell element 40
3.3 8-noded parent and isoparametric elements 41
3.4 Half-convolution domain for solid element 43
3.5 Distribution of added mass, m12 (x), over the 52 length of fixed-fixed bellows (first mode)
3.6 Initiai and deformed shapes of bellows convolution 53
3.7 Division of convolution by planes of symmetry 60
3.8 The solution domain with boundary conditions 62
3.9 20-noded parent and isoparametric elements 65
3.10 Spatial view of3D mesh of 1/8 convolution space 69
3.11 Added mass,, versus h!Rm 75
3.12 Rocking mode of universal expansion joint 79
4.1 Universal expansion joint as elastic system 82
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4.2 Lateral modes: a) first, b) second 82
4.3 Rocking modes: a) first, b) second 83
4.4 Distribution of Coriolis for simply supported 94 ends - 1, and fixed-fixed ends - 2
4.5 Differential element of bellows 97
5.1 Mathematical model for single bellows 10