KAIZER EFFECT IN ACOUSTIC EMISSION EVENT FROM MECHANICAL
TESTING
MD NURAZLAN BIN MD GHAZALI
Report submitted in partial fulfilment of the requirements
for the award of the degree of
Bachelor of Mechanical Engineering
Faculty of Mechanical Engineering
UNIVERSITI MALAYSIA PAHANG
DECEMBER 2010
UNIVERSITI MALAYSIA PAHANG
FACULTY OF MECHANICAL ENGINEERING
I certify that the thesis entitled “Kaizer Effect in Acoustic Emission Event from
Mechanical Testing” is written by Md Nurazlan Bin Md Ghazali. I have examined the
final copy of this thesis and in our opinion; it is fully adequate in terms of scope and
quality for the award of the degree of Mechanical Engineering. I herewith recommend
that it be accepted in fulfilment of the requirements for the degree of Mechanical
Engineering.
Mr Abdul Rahim Bin Ismail Signature
Lecturer Faculty of Mechanical Engineering
Universiti Malaysia Pahang
ii
SUPERVISOR’S DECLARATION
I hereby declare that I have checked this project report and in our opinion this project is
satisfactory in terms of scope and quality for the award of the degree of Bachelor of
Mechanical Engineering.
Signature:
Name of Supervisor: CHE KU EDDY NIZWAN BIN CHE KU HUSIN
Position: Lecturer Faculty of Mechanical Engineering
Date: 6 DECEMBER 2010
iii
STUDENT’S DECLARATION
I hereby declare that the work in this report is my own except for quotations and
summaries which have been duly acknowledged. The report has not been accepted for
any degree and is not concurrently submitted for award of other degree.
Signature:
Name: MD NURAZLAN BIN MD GHAZALI
ID Number: MA08019
Date: 6 DECEMBER 2010
iv
ACKNOWLEDGEMENT
I am very grateful to the ALLAH SWT for making it possible for me to
complete this thesis. It is pleasure to acknowledge the help and support of everyone
concerned with this final year project. To my father, mother, brother and sister, I am
also grateful for their sacrifice, patience, and understanding that were inevitable to make
this work possible. Also for Sayyidina Muhammad saw, blessings and greetings for
him.
I am grateful and would like to express my sincere gratitude to my supervisor,
Mr Che Ku Eddy Nizwan Bin Che Ku Husin for his germinal ideas, invaluable
guidance, continuous encouragement and constant support in making this thesis
possible. I am truly grateful for his progressive vision.
Finally, I wish to thanks to lecturers and lab instructor for their suggestions and
support on this project. Also, thanks to all my friends who have involved and helped me
in this project.
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ABSTRACT
This thesis presents the Kaizer Effect in acoustic emission event from mechanical
testing. Acoustic emission is a transient elastic wave generated by the rapid release of
energy from localized source or sources within a material according to the ASTM
E1316 standard. The purpose of this project is to study acoustic emission (AE)
properties from mechanical testing during reload of specimen until fracture. The
laboratory experiments are carried up in this project. The acoustic emission (AE) signal
acquired on mild steel and aluminium specimens from tensile test and torsion test under
reload-unload loading profile. Kaizer effect of acoustic emission in mild steel and
aluminium, were validated by the experiment. The experimental results will show the
event between the specimens. Acoustic emission (AE) sensors are used to detect AE
event in stress situation. Each loading cycle would cause new damage inside the
material and the response of material to the new loading cycle is different from the
previous cycle. The parameter in acoustic emission such as energy, hits and RMS were
recorded and analyzed from this experiment. As a result, almost all of tensile test
method was achieve the Kaizer effect theory although certain of cycles have an error
cause of external disturbance. From the observations, the hits data, energy and RMS
data for mild steel show the large value compare to aluminum specimen. For torsion
test, all graphs of hits, energy and RMS look similar with each other. The AE event
generated continuously although the loading is in released condition. This situation
mentions that, the method of torsion test is not suitable to carry out the Kaizer effect
study. For the future work, this project can be further by changing another method to
replace the torsion test method. Other method such as fatigue test also can be used to
study Kaizer effect in acoustic emission. The scope of this research also can be
expanded and developed with add more materials to analyze.
vii
ABSTRAK
Tesis ini membentangkan kajian kesan Kaizer yang berlaku pada pancaran akustik (AE)
melalui ujian mekanikal. Pancaran akustik (AE) adalah gelombang elastik yang
dihasilkan oleh pelepasan suatu tenaga yang pantas daripada sesuatu sumber atau
sumber-sumber asal dalam sesuatu bahan dengan merujuk kepada piawaian ASTM
E1316. Objektif untuk projek ini adalah untuk mengkaji isyarat pancaran akustik (AE)
ketika sesuatu spesimen dikenakan beban secara berulang- ulang sehingga berlakunya
kegagalan. Eksperimen di dalam makmal telah dilakukan untuk menjalankan projek ini.
Isyarat untuk pancaran akustik (AE) diperolehi pada spesimen keluli lembut dan
aluminium dengan mengenakan ujian terikan dan ujian kilasan di bawah beban yang
dikenakan secara berulang-ulang. Kesan Kaizer pada pancaran akustik yang terhasil
pada keluli lembut dan aluminum akan dianalisa di dalam eksperimen ini. Keputusan
daripada eksperimen menunjukkan beberapa perbandingan dan perbezaan di antara
setiap spesimen. Ketika beban dikenakan di dalam eksperimen, penderia pancaran
akustik (AE) digunakan untuk mengesan tindak balas pancaran akustik (AE) yang
berlaku. Setiap kitaran beban akan menyebabkan kerosakan baru pada bahan dan tindak
balas untuk kitaran beban yang baru berbeza daripada kitaran terdahulu. Parameter
seperti tenaga, punca min kuasa dua (RMS) dan jumlah hitungan semasa ujian
pemerolehan data pancaran akustik (AE) direkodkan dan dianalisis dari eksperimen ini.
Hampir kesemua ujian pancaran akustik yang menggunakan kaedah ujian terikan
menepati teori kesan Kaizer walaupun terdapat sedikit ralat pada sesetengah kitaran
akibat dari gangguan luaran. Daripada pengamatan yang dijalankan, jumlah hitungan,
tenaga dan data punca min kuasa dua (RMS) untuk keluli lembut memaparkan nilai
yang lebih besar berbanding dengan spesimen aluminium. Untuk uji kilasan, semua
jumlah hitungan, tenaga dan punca min kuasa dua (RMS) kelihatan sama di antara satu
sama lain. Isyarat bagi pancaran akustik (AE) dihasilkan secara terus-menerus meskipun
tiada beban dikenakan. Situasi ini menunjukkan bahawa, kaedah ujian kilasan tidak
sesuai untuk digunakan di dalam kajian kesan Kaizer. Kajian ini dapat diperbaiki lagi
dengan menukar kaedah lain yang lebih sesuai untuk menggantikan kaedah ujian
kilasan. Kaedah lain seperti ujian kelesuan juga boleh digunakan untuk menganalisa
kesan Kaizer dalam pancaran akustik. Ruang lingkup kajian ini juga boleh diperluas dan
diperkembangkan dengan cara mempelbagaikan lagi jenis bahan untuk dianalisa.
viii
ix
TABLE OF CONTENTS
Page
APPROVAL DOCUMENT ii
SUPERVISOR’S DECLARATION iii
STUDENT’S DECLARATION iv
ACKNOWLEDGEMENTS vi
ABSTRACT vii
ABSTRAK viii
TABLE OF CONTENTS ix
LIST OF TABLES xii
LIST OF FIGURES xiii
LIST OF SYMBOLS xviii
LIST OF ABBREVIATIONS xix
CHAPTER 1 INTRODUCTION
1.1 Project Background 1
1.2 Problem Statement 2
1.3 Objectives 3
1.4
1.5
Hypothesis
Scopes of Research
3
4
CHAPTER 2 LITERATURE REVIEW
2.1 Introduction 5
2.2 Mechanical Testing 5
2.2.1 Tensile Test 6
2.2.2 Testing Machine for Tensile Test 6
2.2.3 Tensile Specimen 7
2.2.4 Stress-Strain Curve 8
2.2.5 Fracture Characteristics of Tested Specimens 14
2.2.6 Torsion Test 16
2.2.7 Torsion Specimen and Testing Machine 17
2.2.8 Fundamental Principles of the Torsion Test 19
1 × ENTER (1.5 line spacing)
x
2.2.9 Fracture Characteristic of Tested Specimen 24
2.3 Types of Materials 26
2.3.1 Aluminum and Aluminum Alloys 26
2.3.2 Chemical Composition 26
2.3.3 Specification of Aluminum 27
2.3.4 Mild Steel 28
2.3.5 Characteristic of Mild Steel 29
2.4 Acoustic Emission (AE) 30
2.4.1 Introduction to the Acoustic Emission 30
2.4.2 Concept of Acoustic Wave Propagation 31
2.4.3 Parameter of Acoustic Emission (AE) Signal 32
2.4.4 Kaiser Effect and Felicity Effect 34
2.5 Equipment Used in AE Monitoring 35
2.5.1 Sensor 35
2.5.2 Couplant and Holders 36
2.5.3 Pre-Amplifiers 36
2.5.4 Data Acquisition System 36
2.6 AE Signal Parameter Analysis 37
2.7 Application of Acoustic Emission 39
CHAPTER 3 METHODOLOGY
3.1 Introduction 41
3.2 Project Flow Chart 42
3.3 Literature Review 43
3.4 Material Selection 43
3.5 Sample Preparation 44
3.6 Acoustic Emission Test Setup 47
3.6.1 Testing Procedure 47
3.6.2 Test Setup 48
3.6.3 Sensor Calibration Test 51
3.6.4 Loading Profile 52
3.7 Data Flow Analysis 53
xi
CHAPTER 4 RESULT AND DISCUSSION
4.1 Introduction 56
4.2 Tensile Test Experiment 56
4.3 Torsion Test Experiment 61
4.4 Discussion 65
4.4.1 Hits Data for Aluminum Material 65
4.4.2 Energy Data for Aluminum Material 67
4.4.3 RMS Data for Aluminum Material 69
4.5 Mild Steel Specimen 70
4.5.1 Hits Data for Mild Steel Material 70
4.5.2 Energy Data for Mild Steel Material 72
4.5.3 RMS Data for Mild Steel Material 73
CHAPTER 5 CONCLUSION AND RECOMMENDATION
5.1 Conclusion 76
5.2 Recommendation 77
REFERENCES 78
APPENDICES 80
A1-A8 AE Data for each experiment 80
B1 MATLAB cording for acoustic emission data analyzing 112
C1 Gantt Chart 113
1 × ENTER (1.5 line spacing)
xii
LIST OF TABLES
Table No. Title Page
2.1 Dimensional relationships of tensile specimen used in various
countries
8
2.2 Properties of selected aluminum alloys at room temperature 28
2.3 Composition of mild steel 29
2.4 Standard properties of mild steel 29
3.1 Details dimension for tensile specimen 46
3.2 Detail dimension for torsion specimen 47
3.3 Loading schedule for tensile test 53
3.4 Loading schedule for torsion test 53
xiii
LIST OF FIGURES
Figure No. Title Page
2.1 UTM Tensile Test Apparatus (electromechanical) 7
2.2 Standard tensile specimen 8
2.3 Stress-strain relationship under uniaxial tensile loading 9
2.4 Stress-strain curve of low carbon steel and aluminum 11
2.5 Determination of the yield strength at 0.2% offset 12
2.6 Necking of a tensile specimen occurring prior to fracture 13
2.7 Cup and cone fracture 15
2.8 Ductile fracture surface 15
2.9 Brittle fracture surface 15
2.10 Torsion in cylindrical bar 16
2.11 Torsion testing machine 17
2.12 Torsion specimen 18
2.13
2.14
2.15
Schematic diagram of torsion test
Relationship between torque and angle twist
Torsion of a solid bar
18
19
20
2.16 Relationship between modular shear stress and shear strain 23
2.17
2.18
Types of failure in torsion
Fracture surface of a driveshaft in brittle under torsion
24
25
2.19 Fracture surface of driveshaft in ductile under torsion 25
2.20 Principle of acoustic emission 31
2.21 Transient signal 32
2.22 Continuous signal 32
xiv
2.23 A typical AE signal 33
2.4 Stress-strain curve of low carbon steel and aluminum 11
2.5 Determination of the yield strength at 0.2% offset 12
2.6 Necking of a tensile specimen occurring prior to fracture 13
2.7 Cup and cone fracture 15
2.8 Ductile fracture surface 15
2.9 Brittle fracture surface 15
2.10 Torsion in cylindrical bar 16
2.11 Torsion testing machine 17
2.12 Torsion specimen 18
2.13 Schematic diagram of torsion test
18
2.14 Relationship between torque and angle twist 19
2.15 Torsion of a solid bar 20
2.16 Relationship between modular shear stress and shear strain 23
2.17 Types of failure in torsion
24
2.18 Fracture surface of a driveshaft in brittle under torsion
25
2.19 Fracture surface of driveshaft in ductile under torsion 25
2.20 Principle of acoustic emission 31
2.21 Transient signal 31
2.22 Continuous signal 32
2.23 A typical AE signal 32
2.24 Plot illustrating cycling loading and breakdown of the Kaiser
Effect
34
2.25 Common types of AE sensor 35
xv
2.26 Magnetic holder 36
2.27 Data Acquisition system 37
2.28 Cumulative plot of events v/s time 38
2.29 Plot of load history along with cumulative hits 38
3.1 Project flow chart 42
3.2 Types of material 43
3.3 Shearing machine 44
3.4 Die set for tensile specimen 44
3.5 Stamping process 45
3.6 Engineering drawing for tensile test specimen 45
3.7 Lathe machine 46
3.8 Torsion specimen 47
3.9 USB-AE-Node unit 48
3.10 Integral preamplifier AE piezoelectric sensor 48
3.11 Detail of the AE test setup from tensile testing 49
3.12 Detail of the test setup for torsion test 50
3.13 Mild steel adaptor for torsion test 50
3.14 Aluminum adaptor for torsion test 50
3.15 Pencil break calibration 51
3.16 Stress schedule for Kaiser Effect 53
3.17 The AE flow process analysis 54
4.1 First experiment for aluminum tensile test 57
4.2 Hits and energy from first experiment for aluminum tensile test 57
4.3 Second experiment for aluminum tensile test 57
xvi
4.4 Hits and energy from second experiment for aluminum tensile test 58
4.5 First experiment for mild steel tensile test 59
4.6 Hits and energy from first experiment for mild steel tensile test 59
4.7 Second experiment for mild steel tensile test 60
4.8 Hits and energy from second experiment for mild steel tensile test 60
4.9 First experiment for aluminum torsion test 61
4.10 Hits and energy from first experiment for aluminum torsion test 62
4.11 Second experiment for aluminum torsion test 62
4.12 Hits and energy from second experiment for aluminum torsion test 63
4.13 First experiment for mild steel torsion test 63
4.14 Hits and energy from first experiment for mild steel torsion test 64
4.15 Second experiment for mild steel torsion test 64
4.16 Hits and energy from second experiment for mild steel torsion test 65
4.17 Force and data hit versus time for aluminum tensile test
experiment
66
4.18 Force and data hit versus time for aluminum torsion test
experiment
67
4.19 Force and energy versus time for aluminum tensile experiment 68
4.20 Force and energy versus time for aluminum torsion experiment 68
4.21 Force and RMS versus time for aluminum tensile experiment 69
4.22 Force and RMS versus time for aluminum torsion experiment 70
4.23 Force and data hit versus time for mild steel tensile test
experiment
71
4.24 Force and data hit versus time for mild steel torsion test
experiment
71
4.25 Force and energy versus time for mild steel tensile test experiment 72
xvii
4.26 Force and energy versus time for mild steel torsion test experiment 73
4.27 Force and RMS versus time for mild steel tensile test experiment 73
4.28 Force and RMS versus time for mild steel torsion test experiment 74
xviii
LIST OF SYMBOLS
mm Millimeter
Mps Megapascal
MT Torsion moment
GPa Gigapascal
% Percent
kN Kilonewton
Nm Newton meter
kHz Kilohertz
Stress
P Load
A0 Cross sectional area
Strain
Instantaneous length
Original length
Modulus of elasticity
Decibel
Vs
Nm
Energy
Torque
xix
LIST OF ABBREVIATIONS
UMP University of Malaysia Pahang
FKM Fakulti Kejuruteraan Mekanikal
ASTM American Society for Testing and Material
AISI American Iron and Steel Institute
NDT Nondestructive Testing
AE Acoustic Emission
RMS Root Mean Square
1
CHAPTER 1
INTRODUCTION
1.1 PROJECT BACKGROUND
Acoustic emission (AE) has been described as a transient elastic wave generated
by the rapid release of energy from a localized source or source within a material.
(ASTM E1316 2009). The transient elastic waves will take a form of displacement
vibration in the material which can be detected by displacement gauges or accelerator
gauges. These gauges are called AE transducers. AE is related to the internal changes of
material structure which are caused by external physical one action, such as load and
temperature.
Since the acoustic emission (AE) technique detects stress waves generated during
the transient release of stored strain energy in materials subjected to external mechanical
loads, material state and fracture mechanisms may be evaluated in a non-destructive
manner by analyzing AE data. Thus, the AE measurement method has been applied to
tasks in many engineering fields, such as the real-time evaluation of safety and
reliability of civil engineering and architectural structures (Yuyama et. al 1994),
mechanical and aerospace structures (Cherfaouie et. al 1998) manufacturing processes
(Choi et al. 1992) as well as advanced materials (Hoshino, 1992)
For mechanical testing, the applied load may be controlled by the examiner or
may already exist as part of the process. In either case the applied load is measured
along with the AE activity. Consequently the emission activity must be evaluated in
relation to the applied load. AE reveals the internal fracturing and deforming processes
within. AE will start when the load on specimens exceeds some level, and the intensity
2
of AE will increase with increasing loads. For this study, the Kaiser Effect within
specimens subjected to a tensile and torsion load have been evaluated by the AE
features during the whole loading period.
The Kaizer effect is an AE phenomenon briefly defined as the absence of
detectable acoustic emissions until the previously applied stress level is exceeded. This
effect is based on the experimental discovery by Kaizer in Germany during 1945-1950,
that metal materials had the capability to remember the previous maximum stress level.
1.2 PROBLEM STATEMENT
Kaizer first noted high frequency bursts of energy or acoustic emission, during
tensile tests in metals (Kaiser, 1950). By uniaxially loading a rock sample until acoustic
emission is detected, it can determine the maximum stress. However, the Kaizer Effect
is easy to demonstrate and in this study we have attempted to provide corroborative
evidence that the stresses we have measured are indeed the principal stresses in the
reservoir.
In the previous demonstration and in the remainder of this work we have utilized
acoustic emission onset directly as the indicator of maximum stress. Some researchers
apply Kaizer Effect in acoustic emission. From their research, some method of acoustic
emission test is done from several mechanical testing such as fatigue and tensile testing.
In this thesis, new types of mechanical testing have been chosen. Torsion test
have been chosen to apply Kaizer Effect in acoustic emission using aluminum and mild
steel material. The tensile test also done for this experiment and the analysis of the
result will do with this two mechanical testing.
3
1.3 OBJECTIVES
The main objectives for this research are:
i. To study about acoustic emission (AE) event and analyze the signal
parameter during load-unload method to the specimen from mechanical
testing under Kaizer Effect.
ii. To compare the specimen result using acoustic emission testing with
different types of mechanical testing.
1.4 HYPOTHESES
In this research, some of hypotheses have done such as:
i. The applying load for Kaizer Effect in acoustics emission test is same
value, so the prediction of the result for each experiment of torsion test
will be same with the tensile test.
ii. From Kaizer Effect in acoustics emission, the curve for each experiment
of loading versus time shows the different value. The curve depends to
the properties of material and will be show that the maximum load for
mild steel is greater than the maximum load for aluminum.
iii. From the Kaizer result, more acoustic event is observed when the repeat
increasing load or stress is applied in the experiment. However, there has
no acoustic emission when the load for cycle two is not exceeding than
the peak of cycle one.
4
1.5 SCOPE OF RESEARCH
For this research, the acoustic emission testing will be done to detect a signal
from mechanical testing. Nowadays, a lot of mechanical testing has be produce to
analyze the properties of materials. Tensile and torsion test is a few types of mechanical
testing which can apply the loading following the Kaiser phenomenon. The result from
the test will be analyzed according to the acoustic emission technique.
With the different types of mechanical testing, the properties of the specimen
will be comparing. Also, two types of materials were carried out during the experiment
of this research. Aluminum and mild steel has been choosing for this experiment. From
this experiment also want to study the parameter of acoustic emission event such as hits
and energy. Data from acoustic emission parameter will be analyzed to get the
characteristic of acoustic.
5
CHAPTER 2
LITERATURE REVIEW
2.1 INTRODUCTION
The purpose of this chapter is to provide a review of past research efforts related
to mechanical testing, types of materials and acoustic emission testing. A review of
other relevant research studies also provides. The review is organized chronologically to
offer insight to how past research efforts have laid the groundwork for subsequent
studies, including the present research effort.
2.2 MECHANICAL TESTING
Mechanical testing is carried out to produce data that may be used for design
purposes or as part of a material joining procedure or operator acceptance scheme. The
most important function may be that of providing design data since it is essential that
the limiting values that a structure can withstand without failure are known. Inadequate
control of the material properties by the supplier, or incompetent joining procedures and
operatives are, however, equally crucial to the supply of a product that is safe in use.
An example of mechanical testing is the tensile and torsion test that may be used
either to determine the yield strength of steel for use in design calculations or to ensure
that the steel complies with a material specification's strength requirements. The
purposes of mechanical testing are to get a data for design purposes. For the example
tensile test is done to determine the yield strength of steel for design calculation or
torsion test for measure of the ability of a material to withstand a twisting load.
6
Based on the title given, the scope of this project was preferred to study Kaiser
Effect in acoustic emission from mechanical testing equipment. There are a few types of
mechanical testing such as tensile test, torsion test and fatigue test. For this experiment,
tensile test and torsion test is used to analyze the acoustic emission event. In this review,
material preparation also should identify and must be chose to conduct this experiment.
2.2.1 Tensile test
Tensile test is a method for determining behavior of materials under axial stretch
loading (ASTM E8 2008). Data from test are used to determine elastic limit, elongation,
modulus of elasticity, proportional limit, reduction in area, tensile strength, yield
point, Yield Strength and other tensile properties. Tensile tests at elevated temperatures
provide creep data. Procedures for tension tests are given in ASTM E-8. Uniaxial tensile
test is known as a basic engineering test to achieve ultimate strength, yield strength and
ductility of interested materials. These important parameters are useful for the selection
of engineering materials for any applications required.
2.2.2 Testing Machine for Tensile Test
The most common testing machines are universal testers, which test materials in
tension, compression, or bending. Their primary function is to create the stress-strain
curve described in the following section in this chapter. Testing machines are either
electromechanical or hydraulic. The principal difference is the method by which the
load is applied. UTM Tensile Test Apparatus is an electromechanical test machine,
which is used for testing a wide range of materials in tension or compression by moving
the crosshead in an upward or downward direction via drive system. The test specimen
is secured between the rigid frame base and the moving crosshead. The applied load is
measured by a load cell mounted between the test specimen and the crosshead. There
are two different load cells (2kN and 100kN capacity) to provide a range of load
measurement capabilities. UTM Tensile Test Apparatus testing apparatus for tensile test
can be shown as the Figure 2.1.
