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