UNIVERSITI PUTRA MALAYSIA
ALAA RAAD HUSSEIN
FK 2010 66
EFFECT OF VIBRATION FREQUENCIES ON THE WELDING PROPERTIES OF RECTANGULAR MILD STEEL PLATE
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EFFECT OF VIBRATION FREQUENCIES ON THE WELDING
PROPERTIES OF RECTANGULAR MILD STEEL PLATE
By
ALAA RAAD HUSSEIN
Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,
in Fulfilment of the Requirements for the Degree of Master of Science
November 2010
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DEDICATION
This work is dedicated to:
My mother,
Your encouragement and comforting words are a tonic for my soul.
My father,
Your dynamic and generous spirit continues to enrich my life.
My brother & sisters,
Your friendship is a treasure beyond compare.
My fiancée Zuhor,
Your love is inspired me during this long journey.
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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment
of the requirement for the degree of Master of Science
EFFECT OF VIBRATION FREQUENCIES ON THE WELDING
PROPERTIES OF RECTANGULAR MILD STEEL PLATE
By
ALAA RAAD HUSSEIN
November 2010
Chairman : Nawal Aswan Abd Jalil, PhD
Faculty : Engineering
The welding process induces potential deflection, which significantly affects the
ultimate strength behaviour of the welded structure. The deflection can result in
many problems that can have an adverse effect on the accuracy of the assemblage
part, external appearance or strength characteristics of the welded metal. The main
aim of this study is to identify a relationship between the induced vibration and
welding temperature including the properties of welding in order to obtain the
deflection that occurs on the plate’s surface. In addition, the effect of frequency
during welding on the mechanical properties of the welding fusion metal was also
investigated. Four different values of frequencies were investigated (3, 5, 10 and
100) Hz and applied on a rectangular plate with dimension (400 x 200 x 6) mm. The
strain was measured at the area close to the middle surface and on the transverse
direction (at the edge, 20, 40, 60 and 90) mm from the edge. The theoretical results
showed that the maximum value of the deflection occurs at the middle surface and it
decreases on the transverse direction downward to the edge. Further more the effect
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of varying temperature and frequency on the measured strain provides the same
behaviour of deflection at the middle surface and it decreases on the transverse
direction downward to the edge, which started at 3.9 micro strain at the edge when
both of welding and 100 Hz are applied and kept increasing to reach the maximum
value at the middle 7.8 micro strain when the 100Hz are applied. The applied
vibration during welding resulted in an improvement of about 50% for tensile
strength and maximum load of 29076.68 N for the ductility of the filler metal due to
the fine distribution of the filler metal by the effect of vibration. The increase in the
frequency value during welding process led to reduce the micro crack that generated
inside the fusion filler metal which generated because of high welding temperature.
In conclusion, the applied frequency and thermal load at the centre of the plate
surface generate plate deflection and resulted in less value of deflection on the
transverse direction than the centre. In addition, these forces led to increase in the
strain value at the centre of the plate. The applied vibration during welding results in
a fine distribution of the filler metal and increased the ductility and the tensile
strength of the filler metal. This increasing in the mechanical properties provides a
good indicator of the positive effect of induced vibration on welds.
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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai
memenuhi keperluan untuk ijazah Master Sains
PENGARUH GETARAN FREKUENSI TENTANG PENGELASAN
PROPERTI Dari PERSEGI MILD STEEL PLAT
Oleh
ALAA RAAD HUSSEIN
November 2010
Pengerusi : Nawal Aswan Abd Jalil, PhD
Fakulti : Kejuruteraan
Proses pengimpalan berpotensi mendorong defleksi yang mana memberi kesan
secara signifikan kepada perilaku kekuatan struktur logam yang telah diimpal.
Defleksi ini boleh menyebabkan banyak masalah yang mempunyai kesan negatif
pada ketepatan bahagian himpunan, penampilan luaran atau kekuatan sifat logam
yang diimpalkan. Tujuan utama kajian ini adalah untuk mengenalpasti hubungan
antara getaran induksi dan suhu pengimpalan termasuk ciri-ciri pengimpalan yang
menyebabkan defleksi terjadi pada permukaan logam. Selain itu, kesan frekuensi
semasa proses pengimpalan terhadap sifat mekanik dari pengimpalan logam yang
dicantum juga diselidik. Empat nilai frekuensi yang berbeza yang diselidik iaitu (3,
5, 10 dan 100) Hz. Untuk kesemua empat frekuensi itu, defleksi plat logam dikira
secara teori di tengah permukaan dan pada arah melintang. Regangan diukur pada
kawsasan berhampiran dengan permukaan tengah dan pada arah melintang (di tepi,
20, 40, 60 dan 90) mm dari sisi. Keputusan secara teori menunjukkan bahawa nilai
maksimum defleksi berlaku pada permukaan tengah dan berkurangan pada arah
melintang ke bawah menuju ke tepi. Dikenalpasti bahawa suhu yang berbagai
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mempunyai kesan lebih mendalam kepada defleksi plat berbanding daripada
frekuensi yang berbagai, selain itu pengaruh variasi suhu dan frekuensi pada
regangan yang diukur memberikan defleksi yang sama perilaku pada tengah
permukaan dan menurun pada arah melintang ke bawah menuju ke tepi. Getaran
yang digunakan semasa pengimpalan menghasilkan peningkatan sekitar 50% untuk
kelenturan dan kekuatan ketegangan oleh filet logam. Peningkatan nilai frekuensi
semasa proses pengimpalan membantu untuk mengurangkan retakkan mikro yang
terhasil di dalam cantuman filet logam disebabkan oleh ketinggian suhu
pengimpalan. Penyelesaian bentuk matematik disimpulkan untuk getaran induksi dan
beban termal telah diterbitkan untuk menunjukkan secara teori perilaku defleksi pada
tengah dan pada arah melintang.
Kesimpulannya, penggunaan frekuensi dan beban termal di tengah permukaan plat
meningkatkan defleksi plat dan mengakibatkan nilai kecil defleksi pada arah
melintang, juga daya-daya ini membantu meningkatkan nilai regangan di tengah
permukaan. Getaran diterapkan semasa pengimpalan menghasilkan pembahagian
yang halus kepada filet logam dan meningkatkan kelenturan dan kekuatan
ketegangan filet logam. Hal ini meningkatkan sifat mekanik dalam memberikan
penunjuk yang baik dari kesan positif oleh getaran yand diinduksi dari pengimpalan.
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ACKNOWLEDGEMENTS
Thanks to Allah for His helping out while I was about to give up and His
unbelievably close support any time I needed.
I owe my deepest gratitude and thanks to my supervisor, Dr. Nawal, who has
supported me to complete my thesis with his patience and knowledge. I attribute the
level of my Masters degree to his encouragement and effort and without him this
thesis, too, would not have been completed or written.
I also would like to appreciate the efforts of the honorable Dr. Abd Rahim for
providing me with fruitful information and giving me a vast visibility in the world of
knowledge.
I also thank all other faculty members who somehow helped me prepare this
assignment.
Last but not least, I would like to express my gratitude to my beloved parents, with
their guidance, supports, love and encouragement.
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I certify that a Thesis Examination Committee has met on 24 of Nov. 2010 to
conduct the final examination of Alaa Raad Hussein on his thesis entitled “The effect
of vibration frequencies on the welding properties of rectangular mild steel plate" in
accordance with the Universities and University Colleges Act 1971 and the
Constitution of the University Putra Malaysia [P.U.(A)] 15 March 1998. The
Committee recommends that the Student be awarded the relevant Master of Science.
Members of the Thesis Examination Committee were as follows:
Mohd Khairol Anuar Bin Mohd Ariffin, PhD
Senior lecturer
Faculty of Engineering
Universiti Putra Malaysia
(Chairman)
Barkawi Bin Sahari, PhD
Professor
Faculty of Engineering
Universiti Putra Malaysia
(Internal Examiner)
B.T. Hang Tuah Bin Baharudin, PhD
Senior lecturer
Faculty of Engineering
Universiti Putra Malaysia
(Internal Examiner)
Che Hassan Bin Che Haron, PhD
Associate Professor
Faculty of Engineering
Universiti Kebangsaan Malaysia
(External Examiner)
BUJANG KIM HUAT, PhD
Professor and Deputy Dean
School of Graduate Studies
Universiti Putra Malaysia
Date:
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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been
accepted as fulfilment of the requirement for the degree of Master of Science. The
members of the Supervisory Committee were as follows:
Nawal Aswan Abd Jalil, PhD
Senior Lecturer
Faculty of Engineering
Universiti Putra Malaysia
(Chairman)
Abd Rahim Abu Talib, PhD
Associate Professor
Faculty of Engineering
Universiti Putra Malaysia
(Member)
HASANAH MOHD GHAZALI, PhD
Professor and Dean
School of Graduate Studies
Universiti Putra Malaysia
Date:
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DECLARATION
I declare that the thesis is my original work except for quotations and citation which
have been duly acknowledged. I also declare that it has not been previously, and is
not concurrently, submitted for any other degree at Universiti Putra Malaysia or other
institutions.
ALAA RAAD HUSSEIN
Date: 24 November 2010
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TABLE OF CONTENTS
Page
DEDICATION ii
ABSTRACT iii
ABSTRAK v
ACKNOWLEDGEMENTS vii
APPROVAL viii
DECLARATION x
LIST OF TABLES xiii
LIST OF FIGURES xiv
LIST OF ABBREVIATIONS xvii
CHAPTER
1 INTRODUCTION 1
1.1 Overview 1
1.2 Motivation of the study 3
1.3 Hypothesis 4
1.4 Objective of the study 4
1.5 Scope of the study 4
1.6 Thesis layout 5
2 LITERATURE REVIEW 7
2.1 Overview 7
2.2 Welding and manufacture 7
2.3 Welding methods and their effects 9
2.3.1 Methods of welding 10
2.3.2 Welding effects on material 21
2.4
2.5
Methods for reduction of welding detriments
Vibration analysis of rectangular plate
25
36
2.6 Natural frequency and mode shape 46
2.7 Summary 52
3 METHODOLOGY 53
3.1 Overview 53
3.2 Kirchoff’s plate theory 54
3.3 Derivation of the stress equation 55
3.4 Derivation of the bending moment equations 59
3.5 Governing equation 62
3.6 The boundary condition and vibration analysis 64
3.6.1 Conditions for solving the partial parts of the
governing equation 64
3.6.2 External force analysis 66
3.7 Closed form solution 67
3.8 Experimental work 68
3.9 Experimental preparations 68
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3.9.1 Material properties 68
3.9.2 Other experimental components 71
3.10 Experimental procedure and work sequence 72
3.10.1 Sequence of work 72
3.10.2 Experimental procedure 72
3.11 Strain measurement and conversion 76
3.12 Mechanical tests 79
3.12.1 Tensile test 79
3.12.2 Bending test 81
3.12.3 Scanning electron microscopy (SEM) 84
3.13 Discussion 85
4
RESULTS AND DISCUSSION 86
4.1 Overview 86
4.2 Theoretical results 86
4.2.1 Natural frequency 83
4.2.2 The deflection at the middle surface of the plate 87
4.2.3 Deflection on the transverse direction 90
4.3 Experimental results 93
4.3.1 The natural frequency of the plate 94
4.3.2 Generated strain 101
4.4 Mechanical result 108
4.4.1 Bend result 108
4.4.2 Tensile result 112
4.5 Scanning electron microscopy result 115
4.6 Evaluation and comparison of the results 121
4.7 Summary 127
5 CONCLUSIONS AND RECOMMENDATIONS 129
5.1 Conclusions 129
5.2 Recommendations for further works 131
REFERENCES 132
APPENDIX 1 138
BIODATA OF STUDENT 142
LIST OF PUBLICATION 143