iv

ABSTRACT

This study is carried out to develop a computerized ultrasonic-based measurement system for mechanical properties and acoustical characterization of non-porous solids materials. The system employed the pulse-echo method using both longitudinal and shears waves. This system consists of a pulser/receiver generator, transducers, picoscope and personal computer. The developed system offers user-friendly procedure, yet producing accurate and reliable measurement results. The software for the system is developed using Microsoft Visual Basic Version 6.0. The front panel display is divided into the connection and control panel, the display panel and the calculation panel. The programming code for software algorithm is divided into the connection programming code, the control programming code, the display programming code and the calculation programming code. There are eight parameters of the mechanical and acoustical properties of solids materials are discussed in this study; longitudinal velocity, shear velocity, acoustical impedance, Poisson’s ratio, Young modulus, Bulk modulus, Shear modulus, and compressibility. The performance of the system is tested on 4 different types of solid materials; acrylic, aluminum, mild steel and copper. The results proved that the developed system is suitable for nonporous solid materials and the measurement error compare to the references is acceptable. However, to assess the ability of this developed system, more measurement in variety of test material should be carried out.

v

PEMBANGUNAN SISTEM BERSEPADU ULTRASONIK UNTUK MENGUKUR UNSUR DAN CIRI-CIRI MEKANIKAL DAN AKUSTIK

BAHAN PEPEJAL

ABSTRAK

Kajian ini dijalankan untuk membina sistem pengukuran ultrabunyi berkomputer untuk pencirian mekanikal dan akustik bagi bahan pepejal. Sistem dibina dengan kaedah gema-denyut menggunakan gelombang membujur dan ricih. Sistem yang dibina terdiri daripada penjana pendenyut-penerima, transduser, pikoskop dan komputer. Perisian untuk sistem tersebut dibina dengan menggunakan Microsoft Visual Basic Versi 6.0. Sistem yang dibina menggunakan prosedur yang mesra pengguna, menghasilkan keputusan yang mempunyai kebolehpercayaan dan ketepatan yang tinggi. Paparan antaramuka perisian tersebut terdiri daripada panel sambungan dan kawalan, panel paparan dan panel pengiraan. Kod program untuk algoritma perisian pula terdiri daripada kod sambungan, kod kawalan, kod paparan dan kod pengiraan. Terdapat lapan ciri mekanikal dan akustik yang dibincangkan dalam kajian ini iaitu halaju membujur, halaju ricih, galangan akustik, nisbah Poisson, modulus Young, modulus pukal, modulus ricih, dan kebolehmampatan. Sistem yang dibina diuji ke atas 4 jenis bahan pepejal yang berbeza iaitu perspex, aluminium, besi dan tembaga. Keputusan daripada sistem yang dibina membuktikan bahawa sistem tersebut sesuai untuk bahan pepejal yang tidak berliang dan bacaa ralat pengukuran dibandingkan dengan nilai rujukan adalah boleh diterima. Walaubagaimanapun, untuk menguji kemampuaan sistem yang dibina, lebih banyak pengukuran perlu dilakukan pada pelbagai jenis bahan pepejal.

vi

TABLE OF CONTENT

Page

DECLARATION ii

ACKNOWLEDGEMENT iii

ABSTRACT iv

ABSTRAK v

LIST OF CONTENT vi

LIST OF FIGURES x

LIST OF TABLES xii

LIST OF SYMBOLS xiii

CHAPTER 1 INTRODUCTION

1.1 Introduction 1

1.2 Background of Study 2

1.3 Problems Statement 5

1.4 Introduction of Computer-based Ultrasonic for Mechanical and Acoustical Characterization of Solid Materials System

7

1.5 Research Objectives 8

1.6 Research Questions 9

1.7 Significance of Study 9

1.8 Scope and Limitation of Study 9

1.9 Scope of Report 10

CHAPTER 2 LITERATURE REVIEW

2.1 Introduction 11

vii

2.2 Ultrasonic 11

2.2.1 Type of Ultrasonic wave 13

2.3 Ultrasonic Pulse-echo Technique 14

2.3.1 Pulser/Receiver 15

2.3.2 Transducer 15

2.3.3 Couplant 16

2.3.4 Pulse-echo Operation 17

2.3.5 Oscilloscope 19

2.3.5.1 Digital Oscilloscope 20

2.3.5.2 Data Acquisition 21

2.4 Mechanical and Acoustical Properties of Solid Materials 23

2.4.1 Mechanical Properties of Solid Materials 23

2.4.2 Acoustical Properties of Solid Materials 26

2.5 Summary 28

CHAPTER 3 RESEARCH METHODOLOGY

3.1 Introduction 29

3.2 Mechanical Properties and Acoustical Characteristics Measurement

29

3.2.1 Physical Properties of Sample 30

3.2.2 Mechanical Properties and Acoustical Characteristics Calculation

31

3.1.2.1 Longitudinal and Shear Velocity Determination 32

3.3 The Computer-based UMACS System 34

3.3.1 The Apparatus of UMACS System 35

3.3.1.1 Pulser/Receive Olympus Panametric NDT 5072PR

36

3.3.1.2 USB Oscilloscope Picoscope 3000 Series 36

3.2.1.2.1 Picoscope Application Programing Interface (API)

38

3.4 Development of Computer-based UMACS Software 39

3.4.1 Integrated Development Environment (IDE) Program for The Development of UMACS System

39

3.4.2 User Interface of Computer-based UMACS System 41

viii

3.4.3 Programming Code of the Computer-based UMACS System

44

3.3.3.1 Connection Programming Code of the Computer-based UMACS System

44

3.4.3.2 Control Programming Code of the Computer-based UMACS System

45

3.4.3.3 Display Programming Code of the Computer- based UMACS System

46

3.4.3.4 Calculation Programming Code of the Computer-based UMACS System

47

3.4.4 Flow Chart of the Computer-based UMACS System 48

3.5 Summary 50

CHAPTER 4 RESULTS AND DISCUSSIONS

4.1 Introduction 52

4.2 Performance of the Computer-based UMACS system 53

4.2.1 Glass 53

4.2.2 Aluminum 55

4.2.3 Mild Steel 57

4.2.4 Acrylic 59

4.3 Discussion 61

4.4 Summary 62

CHAPTER 5 CONCLUSION AND RECOMMENDATIONS

5.1 Introduction 63

5.2 Conclusions 64

5.3 Uniqueness of the Computer-based UMACS System 64

5.4 Limitation of the Computer-based UMACS System 65

REFERENCE 66

APPENDICE 68

ix

LIST OF FIGURES

Figure No. Page

1.1 Type of forces applied to the test specimen 4

2.1 Particles vibration in longitudinal and shear wave 13

2.2 Ultrasonic testing Pulse-echo technique setup 14

2.3 Construction of transducer 16

2.4 Couplant spread on the test material 17

2.5 Illustration of traveling wave in sample 18

2.6 Example of pulser/receiver output signal from a pulse-echo test

18

2.7 Oscilloscope 19

2.8 Digital oscilloscope internal systems block diagram 20

2.9 The basic acquisition system 21

2.10 A graph constructed from low sampling rate of an acquisition system

22

3.1 Side view of the sample 30

3.2 Illustrations of travelling sound wave in test material 32

3.3 Example of sound wave result from pulse-echo test 33

3.4 Block diagram of UMACS 34

3.5 Pulser/Receive Olympus Panametric NDT 5072PR 36

3.6 Picoscope 3000 Series 37

3.7 Iconic label of Microsoft Visual Basic Version 6.0 software

39

3.8 Elements of Visual Basic program 40

3.9 Computer-based UMACS System Interface with display tab of longitudinal wave

42

3.10 Computer-based UMACS System Interface with display tab of shear wave

42

3.11 Programming code for setting up the CHANNEL and RANGE column

45

3.12 Programming code when the CONNECT button is clicked 45

x

3.13 Programming code to plot the signal on the display graph 46

3.14 Programming code to calculate the values’ of ACOUSTICAL IMPEDANCE, POISSON’S RATIO, YOUNG MODULUS, SHEAR MODULUS, BULK MODULUS and COMPRESSIBILITY

47

3.15 Flow chart of the computer-based UMACS system 48

3.16 Selected peaks between two reflected sound waves 50

xi

LIST OF TABLE

Table No. Page

3.1 Thickness and density for each sample 31

3.2 Picoscope API’s functions used in UMACS 38

4.1 Comparison between computer-based UMACS system and standard method for mechanical and acoustical properties of glass

53

4.2 Comparison between computer-based UMACS system and standard method for mechanical and acoustical properties of aluminum

55

4.3 Comparison between computer-based UMACS system and standard method for mechanical and acoustical properties of mild steel

57

4.4 Comparison between computer-based UMACS system and standard method for mechanical and acoustical properties of copper

59

xii

LIST OF SYMBOLS

SYMBOL

Density

d Thickness

m Mass

V volume

vL Longitudinal velocity

vS Shear velocity

Poisson’s ratio

E Young Modulus

G Shear modulus

K Bulk modulus

B compressibility

CHAPTER 1

INTRODUCTION

1.1 Introduction

This research involves a study on the development of a computer-based measurement

system to measure the mechanical properties and acoustical characterization of solid

materials. The apparatus to measure the mechanical properties and acoustical

characterization of solid material is by determine the velocities of ultrasound travel in

the test material and the velocities value will be applied in the defined equations to

calculate the mechanical properties and acoustical characteristic. This calculation is

done automatically by computer system. The ultrasonic pulse-echo technique will be

used to determine the velocities travel in material. Ultrasonic testing is the sub method

of the Nondestructive Testing (NDT) or as known as Nondestructive Evaluation

2

(NDE). The system developed use the Ultrasonic NDT instrument integrated with a

computer device. The output signal from the Ultrasonic NDT instrument will be

converted to digital data by the computer device and the data is sent to the computer.

Computer system manipulates the data and display the result.

This chapter consists of six sections; those are background of study, problem

statement, research objectives, research questions, significance of the study, scope and

limitation of the study and scope of the report which is the technology used

extensively in this study.

1.2 Background of Study

The evolvement of today’s technology without exception is essentially corporates

with the material science and engineering field. As the world keeps moving,

manufactories are constantly develops and produces new products. Meanwhile, to

make our live much better, the discovery of new technology makes this world have

possibility to improve the existing products such as vehicles, buildings, machineries

and other necessaries that human needs. Consequently, this modern trend caused the

material science and engineering plays important role in the contributions to the

evolvement of today’s technology. As we can see all things developed and produced

involves of materials.

Generally, material science and technology is an interdisciplinary field which

is concern in a study on structure, properties and behavior of materials and involves

3

the discovery and designing new materials. Material science and engineering

significantly supports the industries, buildings constructions and manufacturing

sectors. Hence, the study to the properties of materials provides important information

for the quality control and material properties determination. The information assist in

selecting a material to use in desired application whether it meet the required

specifications. Technically, with appropriate material are used in any application will

effectively give a good service life time, performances and economically less cost. In

addition, the purpose to measure material properties is for engineering design.

Materials properties are categorized in several types of properties and one of

the categories are mechanical properties. Mechanical properties are the characteristics

of material behavior and reaction when the material is subjected to mechanical

loading or stresses. Most of materials used in buildings construction, vehicles and

industries involves of solid materials such as metals, ceramics, glass, composite

material and etc. Mechanical properties are comprise with properties of elastic

modules (elastic modulus, shear modulus, Poisson's ratio and bulk’s modulus), yield

strength, ultimate stress, elongation and ductility. Overall, mechanical properties such

as elastic modules are significant properties that have to be considered and concerned

when to choose a solid material. The elastic properties of solids are key properties for

the design of mechanically-loaded components (Ashby 1996).

As the name applied, in the early era of material engineering, the conventional

method to determine the mechanical properties is done by mechanical tests. These

tests are destructive testing. The mechanical properties are obtained with several type

of forces applied to the specimens of a material. Each type of forces is used to deform

4

or break the specimens in which to get the useful information to determine some

mechanical properties that is relate to the applied force. These tests required well-

prepared or bulky specimens and involves a period of time. Figure 1.1 shows the type

of forces applied to the test specimen during the mechanical tests.

In contrast to the destructive test, there are several of NDE (nondestructive

evaluation) techniques can be used to characterize mechanical properties, e.g.

electromagnetic, radiometric, and ultrasonic (McMaster, 1959; Green, 1973; Vary,

1973; Krautkramer and Krautkramer, 1977; Hayward, 1978). The speed of wave

propagation and wave energy loss underlie ultrasonic mechanical property

determinations. Accordingly, ultrasonic depends on measuring physical and acoustical

properties via the interaction of elastic stress waves with microstructural and

morphological factors (Mason, 1958; Kolsky 1963; Fu, 1982).

Figure 1.1. Type of forces applied to the test specimen. a) Tension, b) Compression, c) Bending, d) Shear and e) Torsion

a) b) c) d) e)

5

There is an established theoretical foundation and empirical basis for

ultrasonic measurement of elastic moduli (Truell et al., 1969; Schreiber & et al.,

1973). Conversely, ultrasonic assessment of mechanical properties like strength and

toughness are currently based primarily on empirical correlations (Vary, 1978).

Ultrasonic materials characterization may be divided into two major

categories. The first category pertains to measurements that are related to mechanical

properties, e.g. elastic moduli, tensile strength, yield strength, fractures toughness.

The second category pertains to material conditions that govern mechanical properties

and dynamic response, e.g. microstructure, morphology (grain size, shape, and

distribution).

Common applications of ultrasound to NDT are concerned with the detection

and characterization of material flaws or measurement of material thickness.

Ultrasonic measurements can also be used for the characterizations of material

properties such as elastic moduli, material microstructure, hardness, can be estimated

from the ultrasonic measurements (Papadakis 1976; Briks & Jr Green 1991).

1.3 Problem Statement

The standard method to determine mechanical properties are mechanical testing and

destructive testing. The samples or specimen of the test material will be destroyed or

will be broken. This requires amount of samples or bulky size of sample to do several

6

types of testing. This test involves some cost and the testing will be conducted in a

period of time. Moreover, for a new designed material, it may require high cost to test

the material since the material in the phase of research and development in which the

resources are limited. So, the material cannot be provided with large or bulky size of

sample. In contrast, if the designer or researcher is only concern to the basic of

mechanical properties material which are the elastic constants the nondestructive

testing (NDT) is an alternative.

The characterization of mechanical properties by nondestructive evaluation

(NDE) or nondestructive testing (NDT) has been studied for a long time and the

ultrasonic technique has been used for decades. The ultrasonic nondestructive testing

has revolutionized and become more advance for recent years. The growing of

advanced technology in computing and digital processing, make it possible to develop

integrated system of ultrasonic testing integrates with personal computer (PC) and

small portable nondestructive testing instrument have emerged. Ultrasonic testing is

very useful to characterize flaws in a material and to determine some of material

properties such as elastic modules. But, ultrasonic testing equipment are not widely

use and available in Malaysia market. The advanced ultrasonic testing equipment is

totally costly to purchase from abroad.

Therefore, a study should be carried out to focus on the development of the

mechanical and acoustical properties measurement system of the solid materials. The

basic mechanical and acoustical properties are referred to the longitudinal velocity,

shear velocity, acoustical impedance, elastic constant, Poisson’s ratio, Young

modulus, Bulk modulus, Shear modulus and compressibility, which are determined by

7

travelled measurements of ultrasound waves through solid materials under controlled

conditions.

1.4 Introduction of Computer-based Ultrasonic for Mechanical Properties and Acoustical Characterization of Solid Materials System

The computer-based ultrasonic for mechanical and acoustical characterization of solid

materials (UMACS) system is developed to study the relationship between the

mechanical and acoustical characterization of solid materials and the velocity of

ultrasonic waves travel in the materials. The longitudinal velocity and shear velocity

travel in the solid material will be measured and the velocities will be used to

determine six parameters of mechanical and acoustical characterizations of solid

materials; acoustical impedance, Poisson’s ratio, Young modulus, Bulk modulus,

Shear modulus and compressibility.

In the computer-based UMACS system, the ultrasonic waves are produced

using the ultrasonic transducer where the electrical energy exited by a pulser/receiver

generator. The time-domain signal of ultrasonic wave result from the test then will be

converted to digital at the sampling rate of 200 MHz by picoscope and transferred to

the personal computer via Universal Serial Bus (USB) port. The personal computer

system manipulates the data for further processing. The developed computer-based

UMACS system processes the data and measures the velocity of ultrasonic wave

which is used to calculate the mechanical and acoustical characterization of the tested

materials. The system is able to process and calculate the parameters within 5 minutes

compared to the conventional method which require hours to be completed.

8

Besides, the system also does not destroy the tested materials since the

ultrasonic testing technique is a nondestructive testing method. The conventional

method also requires large size and quantity of the test materials for different tests to

determine the mechanical and acoustical characterization of materials because the

conventional method is one type of destructive testing. In contrast, the developed

system only needs small size of the test materials and do not require complicated

samples preparation.

1.5 Research Objective

The objectives of this study are:

1.5.1 To develop a computerized version of non-destructive measurement system to

measure mechanical properties and acoustical characterization for solid

materials. The system will be implemented base-on ultrasonic measurement

techniques.

1.5.2 The ultrasonic-based measurement (Pulse-echo) technique will be used as the

apparatus of this system.

1.5.3 To test the performance of the measurement system on four different types of

solid materials.

9

1.6 Research Questions

1.6.1 How to determine the mechanical properties and the acoustical impedance?

1.6.2 How integrate ultrasonic NDT instrument with personal computer and

manipulated the output from it to get the useful data?

1.6.3 Would be this system will give equal or similar result as the standard

measurement?

1.7 Significant Of Study

At the end of this study, a complete user-friendly measurement system is expected.

The system is accessible to researchers or students who are involved in material

design and intend to determine the mechanical properties of a solid material.

1.8 Scope and Limitation of Study

The main aim of this study is to develop the mechanical properties and acoustical

characterization measurement system. The apparatus used in this system are

pulser/receiver (Olympus Panametric NDT model 5072PR), transducer (Olympus

Panametric NDT 2.25MHz) and USB digital memory oscilloscope (Picoscope 3204).

The measurement system also involves the development of computer-based

system to analyse the acoustic signals generated by Olympus Panametric NDT model

10

5072PR pulser/receiver and determine the mechanical and acoustical properties of the

solid materials. Hence, the digital oscilloscope is connected with the personal

computer via USB port.

The mechanical properties and acoustical characterized measured are

longitudinal velocity, shear velocity, acoustical impedance, Poisson’s ratio, Young

modulus, Bulk modulus, Shear modulus, compressibility and elastic constant. This

study are carried out to test the performance of the system on four different types of

solid materials; glass, aluminum, mild steel and acrylic.

1.9 Scope of Report

This report is divided into six chapters. The first chapter, CHAPTER 1 covers the

background of study, problem statement, research objectives, research questions,

significance of the study and scope and limitation of the study. CHAPTER 2 describes

about ultrasound, ultrasonic testing pulse-echo and the studies of measurement

apparatus system for the mechanical and acoustical characterization of solid materials.

CHAPTER 3 describes about the development of mechanical and acoustical

characterization system, the development of computer-based UMACS, the physical

properties of samples and the measurement of mechanical and acoustical properties of

sample. CHAPTER 4 describes about the performance of the computer-based

mechanical and acoustical characterization system on the solid materials. Finally,

CHAPTER 5 covers the conclusion, uniqueness and limitation of the system.

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

This chapter focuses on the literature review of the research. This chapter consists of

three sections; the ultrasonic, ultrasonic testing pulse-echo technique and mechanical

properties and acoustical characteristics of solid materials

2.2 Ultrasonic

The term of sonic is referred to the sound wave. The sound wave audibility to

the human ear called an audio. Normally, the range of frequency audible for human

12

are between 20 Hz to 20 kHz and the children capable to hear the frequency up to 25

kHz. Ultrasonic is the sound wave beyond the frequency that human can hear.

Ultrasonic is a sound wave with higher frequency than the upper limit of human

audible range (Hendee & Ritenour, 2002).

Ultrasonic sound wave are usually used to penetrate a medium and the

reflection wave or supply focused energy of the ultrasonic sound wave travelled on

targeted medium are useful for many application of instrumentation that is applied in

medical, industrial and material engineering. Ultrasonic not only can be applied in

solid materials, it also can be used to measure the ultrasonic velocity, attenuation

coefficient and characteristic impedance of liquid materials (McClements & Fairley,

1991).

In medical applications, the ultrasonic wave is used to detect and locate any

abnormal growths in human bodies. The ultrasound pulse is transmitted through the

patient’s bodies and the reflected pulse is analysed to determine the location the

abnormal tissue or organ in human bodies. In addition, the ultrasound are also usually

used for relieving rheumatic pain (Njeh, Kearton, Hans, & Boivin, 1998), dental

cutting (Denisova et al., 2009), destroying unicellular organisms, removing kidney

stones and brain tumor without shedding blood (Sumi, Wakabayashi, Tanabe, &

Kubota, 2004) and the movement of velocity of blood flow in human body.

Meanwhile, In industrial application, the ultrasonic wave is used for soldering

and drilling purposes (Shoh, 1975), cutting and welding purposes (Shoh, 1975),

emulsifying immiscible liquids like mercury and water (Shoh, 1975), cleaning of tiny

13

objects like watches (Leighton, 2007; Shoh, 1975) and the sterilization of water and

milk in industrial applications (Shoh, 1975).

2.2.1 Type of Ultrasonic Sound Wave

There are two types of ultrasonic sound waves are commonly used in ultrasonic

testing. The waves are longitudinal and shear. In longitudinal wave, the particles

motion in the medium vibrates parallel to the direction of the wave travels. Since the

longitudinal wave involving the compressional and extensional forces to the medium,

this wave also called as pressure or compressional wave. In Shear wave, the particles

motion in the medium are vibrates perpendicular (transverse) to the direction of the

wave travels. The shear wave also called as transverse wave because of the particles

motion vibrates transversely.

Figure 2.1. Particles vibration in longitudinal and shear wave

Particles at original position

Particles vibration in longitudinal wave

Particles vibration in shear wave

14

2.3 Ultrasonic Testing Pulse-echo Technique

Ultrasonic testing is the one method of a nondestructive testing. There have several

techniques of ultrasonic testing used in material testing. The most common used and

the simplest setup is pulse-echo. In this study, only pulse-echo will be focused since it

the simplest setup.

Figure 2.2 shows the common setup of ultrasonic testing pulse-echo system.

The setup consists of pulser/receiver, transducer and oscilloscope.

Figure 2.2. Ultrasonic testing Pulse-echo technique setup

Pulser/Receiver

Oscilloscope