The Effect Of Probe Frequency In Ultrasonic Testing

karya ini dan pada pandangan saya / kami karya ini

adalah memadai dari segi skop dan kualiti untuk tujuan penganugerahan Ijazah Sarjana Muda Kejuruteraan Mekanikal (Design&Inovasi)

Tandatangan : Nama penyelia I :

Tarikh :

Tandatangan : Nama penyelia II :

NURUL HAFIDZAH BINTI ROSLI

Laporan ini dikemukakan sebagai memenuhi syarat sebahagian daripada syarat penganugerahan Ijazah Sarjana Muda Kejuruteraan Mekanikal (Design&Inovasi)

Fakulti Kejuruteraan Mekanikal Universiti Teknikal Malaysia Melaka

“Saya akui laporan ini adalah hasil kerja saya sendiri kecuali ringkasan dan petikan yang tiap-tiap satunya saya telah jelaskan sumbernya”

Tandatangan : Nama Penulis :

ACKNOWLEDGEMENT

Greatest thanks to Allah Almighty for His blessings and giving me the ability to finish this project, which hopefully can contribute in further research.

I would like to express my gratitude and appreciation to my respectful lecturer supervisor, Mrs. Zakiah bt. Abd Halim for her supervision, invaluable advice and inspiring encouragement in guiding me in completing this research.

Further acknowledgements also to all lecturers and technicians at Faculty of Mechanical Engineering at UTeM for their technical support and help during the completion of this work. Especially to Mr. Rizal from NDT Lab who help sincerely throughout Ultrasonic Testing experiment. Not forgotten to Mr. Sahar and all staff in Advanced Manufacturing Centre that help in manufacturing process even though in their hectic schedule.

Last but not least, I would like to express my gratitude and affection to my beloved family and friends for their unconditional support and smile during developing the original version of this style document.

ABSTRACT

ABSTRAK

TABLE OF CONTENT

CHAPTER INDEX PAGE

ACKNOWLEDGEMENTS і

ABSTRACT іі

ABSTRAK ііі

TABLE OF CONTENT v

LIST OF TABLE vііі

LIST OF FIGURE x

LIST OF APPENDIX v

CHAPTER 1 INTRODUCTION 1

1.1 Background of project 2

1.2 Problem statement 3

1.3 Objective 3

1.4 Scope 3

CHAPTER 2 LITERATURE REVIEW 4

2.1 An overview of Ultrasonic 4

2.1.1 Piezo-electric Effect 5 2.1.2 Ultrasonic Processors 6

2.1.3 Ultrasonic Probes 7

CHAPTER INDEX PAGE

2.2 Previous research 9

CHAPTER 3 METHODOLOGY 14

3.1 Introduction 14

3.2 Material 15

3.3 Research design 16

3.4 Design Analysis 17

3.5 Fabrication of Test Sample 19

3.6 Ultrasonic Testing 20

3.6.1 Equipments 21

3.6.2 Procedure 22

3.6.3 Parameter of Study 23

3.6.3.1 Objective: To investigate effect of probe frequency

23

3.6.3.2 Objective: To investigate the effect of test sample material for probe frequency selection

24

CHAPTER 4 RESULT 25

4.1 Effect of Probe Frequency 25

4.2 Effect of Test Sample Material for Probe Frequency Selection

39

4.3 Crack Location 43

CHAPTER 5 DISCUSSION 44

5.1 Introduction 44

CHAPTER INDEX PAGE

5.3 Effect of Test Sample Material for Probe Frequency Selection

47

5.4 Design Factor 49

5.5 Error Analysis 52

CHAPTER 6 CONCLUSION AND RECOMMENDATION 61

6.1 Conclusion 61

6.2 Recommendation 62

REFERENCES 63

BIBLIOGRAPHY 66

LIST OF TABLE

NUMBER TITLE PAGE

3.1 Material Properties for Mild Steel 15

3.2 Material Properties for Aluminum 15

3.3 To Study Effect of Probe Frequency 23

3.4 To Study the Effect of Test Sample Material for Probe Frequency Selection

24

4.1 Result of Backwall for Different Probe Frequency 27

4.2 Result of Crack 1 at Position A to B for Different Probe Frequency

30

4.3 Result of Crack 1 at Position B to C for Different Probe Frequency

31

4.4 Result of Crack 1 at Position C to D for Different Probe Frequency

33

4.5 Result of Crack 3 at Position A to B for Different Probe Frequency

NUMBER TITLE PAGE 4.6 Result of Crack 1 at Position C to D for Different Probe

Frequency

38

4.7 Result of Backwall for Mild Steel and Aluminum 40

4.8 Result of Crack 1 at Position A to B for Mild Steel and Aluminum

41

4.9 Result of Crack 1 at Position A to B for Mild Steel and Aluminum

42

4.10 Result of Crack 6 for Mild Steel and Aluminum 43

5.1 Relative Error for Effect of Probe Frequency Experiment 53

5.2 Relative Error Calculation for Effect of Test Sample Material for Probe Frequency Selection Experiment

56

5.3 Thickness Analysis of Mild Steel 58

5.4 Thickness Analysis of Aluminum 59

LIST OF FIGURE

NUMBER TITLE PAGE

2.1 Acoustic Spectrum [1] 5

2.2 Ultrasonic Processor [4] 6

3.1 Overview of Research Methodology 14

3.2 Flow Process for Research Design 16

3.3 Final Test Sample Drafting and Cross Section 17

3.4 Layered Crack 18

3.5 CNC 5-Axis Face Milling (DMG-DMU250) [22] 19

3.6 Milling Machining Process[23] 20

3.7 Equipment for Ultrasonic Testing 21

3.8 IOW Calibration Block 22

4.1 2 MHz Result for Backwall 26

4.2 4 MHz Result for Backwall 26

4.3 5 MHz Result for Backwall 27

4.4 Crack 1 Cross Section 27

4.5 2 MHz Result for Crack 1 at Position A to B 28

4.6 4 MHz Result for Crack 1 at Position A to B 29

4.7 5 MHz Result for Crack 1 at Position A to B 29

4.8 2 MHz Result for Crack 1 at Position B to C 30

4.9 4 MHz Result for Crack 1 at Position B to C 30

4.10 5 MHz Result for Crack 1 at Position B to C 31

4.11 2 MHz Result for Crack 1 at Position C to D 32

4.12 4 MHz Result for Crack 1 at Position C to D 32

4.13 5 MHz Result for Crack 1 at Position C to D 33

4.14 5 MHz Result for Crack 2 at Position B to C 34

4.15 Cross Section of Crack 3 34

4.17 4 MHz Result for Crack 3 35

4.18 5 MHz Result for Crack 3 36

4.19 Cross Section for Crack 6 37

4.20 2 MHz Result for Crack 6 37

4.21 4 MHz Result for Crack 6 37

4.22 5 MHz Result for Crack 6 38

4.23 4 MHz Result for Aluminum Backwall 40

4.24 4 MHz Result for Aluminum for Crack 1 at Position A to B

40

4.25 4 MHz A-Scan Result for Aluminum at Crack 3 41

4.26 4 MHz A-Scan Result for Aluminum at Crack 6 42

4.27 Crack Location and Shape 43

5.1 Graph Gain & Pulse Delay Versus Frequency for Backwall

45

5.2 A-Scan Backwall for 2 MHz and 5 MHz 45

5.3 Graph Gain & Pulse Delay Versus Frequency for Crack 1 at Position A to B.

47

5.5 A-Scan Back Wall for Mild Steel and Aluminum 48

5.6 A-Scan Crack 1 at Position A to B for Mild Steel and Aluminum

49

5.7 A-Scan Crack 2 at Position B to C for 2 MHz and 5 MHz

50

5.8 A-Scan at Crack 3 for 2 MHz and 5 MHz 50

LIST OF APPENDIX

NUMBER TITLE PAGE

1A GANTT CHART 67

3A Test Sample Design 70

3B Final Test Sample Design 72

3C Crack Cross Section 73

3D The CNC 5-Axis Face Milling Technical Specification 74

3E Test Sample CATprocess File 75

3F Programming 76

3G Machining Process 107

4A A-Scan Result Effect of Probe Frequency Experiment 108

4B A-Scan Result for 4 MHz Aluminum 115

CHAPTER 1

INTRODUCTION

1.1 Background of the project

1.2 Problem Statement

Transducer or probe is one of the basic component for an ultrasonic testing system. It is manufactured in variety of forms, shapes and sizes to suit for varying applications. Selection of correct probe frequency is one of the critical parameter to optimize the Ultrasonic Testing capabilities. Proper selection is important to ensure accurate inspection data as desired for specific applications. Therefore, an investigation is required to specify the suitability of different range of probe frequency.

1.3 Objective

This project is conducted to investigate the effect of selection of probe frequency in Ultrasonic Testing results and specify the suitability of different range of probe frequency in Ultrasonic Testing. In this project, the test sample for the experiment will be design and the suitability of probe frequency in Ultrasonic Testing will be investigated experimentally.

1.4 Scope

CHAPTER 2

LITERATURE REVIEW

2.1 An overview of Ultrasonic

Since the publication of Lord Rayleigh’s work on sound in “The Theory of Sound”; this work explained the nature and properties of sounds waves which led to the development of the techniques that are currently in use in nondestructive testing [2].

Ultrasounds or Ultrasonics is a sound that generated above the human hearing range. Vibrations above 20 KHz are termed “Ultrasonic waves”. 0.5 MHz to 20 MHz is the usual frequency range for ultrasonic flaw detection[2,3]. However, from [1], the frequency range for ultrasonic nondestructive testing and thickness gage is 0.1 MHz to 50 MHz. The Piezo-Electric Effect is used to produce these high frequencies [2,4,5]. Although ultrasound behaves in a similar manner to audible sound, it has a much shorter wavelength. This means it can be reflected off very small surfaces such as defects inside materials. It is this property that makes ultrasound useful for nondestructive testing of materials.

Figure 2.1: Acoustic Spectrum [1]

From the figure above, the part of the spectrum from zero to 16 Hz is below the range of human hearing and is called the ‘Subsonic’, or ‘Infrasonic’ range. From 16 Hz to 20 KHz is known as the ‘Audible’ range and above 20 KHz as the ‘Ultrasonic’ range. Ultrasonic flaw detection uses vibrations at frequencies above 20 KHz.

Most flaw detection takes place between 500 KHz and 20 MHz although there are some applications, for example in concrete, that use much lower frequencies and there are special applications at frequencies above 20 MHz. In most practical applications in steels and light alloys, frequencies between 2 MHz and 10 MHz predominate. Generally the higher the test frequency, the smaller the minimum detectable flaw, but it will be shown in following articles that higher frequencies are more readily attenuated by the test structure. Choosing an appropriate test frequency becomes a compromise between the size of flaw that can be detected and the ability to get sufficient sound energy to the prospective flaw depth [3].

2.1.1 Piezo-electric Effect