1
EXPERIMENTAL STUDY OF ACOUSTIC EMISSION TECHNIQUE FOR
CONCRETE DEFECT DETECTION
HEADER ALI A.
UNIVERSITI TEKNOLOGI MALAYSIA
4
EXPERIMENTAL STUDY OF ACOUSTIC EMISSION TECHNIQUE FOR
CONCRETE DEFECT DETECTION
HEADER ALI A.
A project report submitted in partial fulfilment
of the requirements for the award of the degree of
Master of Engineering (Mechanical)
Faculty of Mechanical Engineering
Universiti Teknologi Malaysia
JUNE 2015
iii
To Family
“To my beloved family, especially my parents, brothers and sisters for supporting me
all the way”
iv
ACKNOWLEDGEMENT
First of all, gratefulness of thanks to our creator, “ALLAH” for this
continuous blessing, which make this work neither the first nor the last.
I would like to express my sincere gratitude to my supervisor Dr. Raja Ishak
Raja Hamzah for his valuable guidance, support and encouragement throughout this
study.
Especially, I would like to send my deep appreciations to my family who
brought me up with love and completely support during my study.
v
ABSTRACT
The process of structural health monitoring (SHM) involves monitoring a
structure over a period of time using appropriate sensors, extracting damage sensitive
features from the measurements made by the sensors and analysing these features to
determine the current state of the structure. Various techniques are available for
structural health monitoring of structures and acoustic emission (AE) is one
technique that is finding an increasing use. Acoustic emission waves are the stress
waves generated by the mechanical deformation of materials. AE waves produced
inside a structure can be recorded by means of sensors attached on the surface.
Analysis of these recorded signals can locate and assess the extent of damage. This
project describes studies on the AE technique for health monitoring of concrete
structures. Crack initiation or structural damage will result in wave propagation in
solid and this can take place in various forms. Propagation of these waves is likely to
be affected by the dimensions, surface properties and shape of the specimen. This, in
turn, will affect source localization. Various laboratory test results will be presented
on source localization, using pencil lead break tests. The results from the tests can be
expected to aid in enhancement of knowledge of acoustic emission process and
development of effective concrete structure diagnostics system.
vi
ABSTRAK
Proses pemantauan kesihatan struktur (SHM) melibatkan pemantauan
struktur dalam tempoh masa dengan menggunakan sensor yang sesuai, mengekstrak
ciri-ciri sensitif kerosakan dari ukuran yang dibuat oleh sensor dan menganalisis ciri-
ciri ini untuk menentukan keadaan semasa struktur. Pelbagai teknik boleh didapati
untuk pemantauan kesihatan struktur bagi struktur dan pancaran akustik (AE) adalah
salah satu teknik yang semakin meningkat penggunaannya. Gelombang pancaran
akustik adalah gelombang tegasan yang dihasilkan oleh perubahan bentuk mekanikal
bahan. Gelombang AE yang dikeluarkan dalam struktur boleh dirakam melalui
sensor yang dipasang di permukaan. Analisis isyarat yang direkodkan ini boleh
mengesan dan menilai tahap kerosakan. Projek ini menerangkan kajian tentang
teknik AE untuk pemantauan kesihatan struktur konkrit. Permulaan retak atau
kerosakan struktur akan menyebabkan perambatan gelombang dalam pepejal dan ini
boleh berlaku dalam pelbagai bentuk. Perambatan gelombang ini berkemungkinan
terjejas oleh dimensi, ciri-ciri permukaan dan bentuk spesimen. Ini seterusnya, akan
memberi kesan kepada penyetempatan sumber. Pelbagai keputusan ujian makmal
akan dibentangkan tentang penyetempatan sumber, dengan menggunakan ujian patah
mata pensil. Keputusan dari ujian boleh dijangkakan untuk membantu dalam
peningkatan pengetahuan proses pancaran akustik dan pembangunan sistem
diagnostik struktur konkrit yang berkesan.
vii
TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF APPENDIX xiv
1 INTRODUCTION 1
1.1 Introduction 1
1.2 Problem Statement 2
1.3 Objectives of Study 3
1.4 Scope of Study 3
1.5 Thesis Organization 3
2 LITERATURE REVIEW 5
2.1 Introduction 5
2.2 Methods of Structural Health Monitoring 6
2.3 Acoustic Emission Technique 7
2.3.1 Advantages Acoustic Emission
Technique 12
2.4 Brief History of the Use of AE Technique 14
2.5 AE Data Analysis Approach 15
viii
2.5.1 Parameter Based Analysis 15
2.5.2 Waveform Based Analysis 19
2.6 AE Wave Modes 20
2.6.1 Longitudinal and Shear Waves 21
2.6.2 Surface Waves 22
2.6.3 Lamb Waves 22
2.7 Instrumentation for AE Monitoring 24
2.8 Signal Processing Tools 29
2.9 AE Generation during Metal Deformation 30
2.10 General Area of Application 32
2.10.1 Application for SHM of Bridges 33
2.11 Challenges in using Acoustic Emission Technique 34
2.11.1 Source Localization 34
2.11.1.1 Time of Arrival Method 34
2.11.1.2 Source Location using Modal
Analysis Technique 38
2.11.2 Noise Removal and Source
Differentiation 39
2.11.3 Damage Quantification for Several
Assailments 43
2.11.3.1 General Methods 43
2.11.3.2 Intensity Analysis using
Historic and Severity Indices 46
2.11.3.3 B-Value Analysis 48
2.11.3.4 Improved b-value (Ib value)
Analysis 50
2.12 Summary 53
3 METHODOLOGY 56
3.1 Introduction 56
3.2 Research Design 56
3.3 Research Equipment 57
3.3.1 The AE Sensor 58
ix
3.3.2 Couplant and Cable 59
3.4 Experimental Procedure of Research Work 60
3.4.1 The Pencil Lead Test Setup and
Procedure 60
3.4.2 Experimental Acoustic Wave Velocity
Test and Procedure 64
3.4.2.1 Acoustic Emission System
Setup 64
3.4.2.2 AE Sensor Installation and
Sensitivity Checking 64
3.4.2.3 Wave Velocity Test 65
3.4.2.4 Experiment AE Damage
Detection with Pencil Lead
Test and Setup 68
3.5 Summary 70
4 RESULTS AND DISCUSSION 72
4.1 Introduction 72
4.2 Wave Velocity Result 73
4.3 Signal Wave Attenuation Result 73
4.4 Damage Source Location Result 76
4.5 Summary 77
5 CONCLUSION AND RECOMMENDATIONS 79
5.1 Conclusion 79
5.2 Recommendations 80
REFERENCES 82
Appendix A 90-94
x
LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Common SHM methods 8
2.2 Materials in which AE has been measured and source
mechanisms causing AE (Kaphle, 2011) 12
2.3 Characteristics of acoustic emission technique compared
with other inspection methods (Pollock, 1989) 14
2.4 Acoustic emission parameters and their information
about the source event (Ozevin, Greve,2004) 18
2.5 Relationships among the crack safety index, crack
growth rate, count rate and ΔK for bridge steels
explained (Kaphle, 2014) 45
3.1 Parameters for evaluating attenuation 61
4.1 Summary of the features of AE signals from pencil lead
test 74
4.2 The contrast of AE signal amplitude between pencil lead
test result and attenuation calculation 75
4.3 Result of experiment damage source location 76
xi
LIST OF FIGURES
FIGURE NO. TITLE PAGE
2.1 Acoustic Emission technique (Carlos, 2003) 11
2.2 Parameters of AE signals (Nair & Cai, 2010) 16
2.3 Energy as measure area under rectified signal
envelope (Song & Saraswathy, 2007) 17
2.4 Continuous and burst AE signals (Gorman, 1998) 20
2.5 (a) Longitudinal and (b) transverse waves
(Kaphle, 2012) 21
2.6 Surface waves (Kaphle, 2012) 22
2.7 Early arriving symmetric (extensional) mode and
later asymmetric (Flexural) modes
(Thambiratnam, 2009) 23
2.8 Symmetric and Asymmetric Lamb waves
(Thambiratnam, 2012) 23
2.9 AE measurement chain (Trujillo, 2014) 24
2.10 Different types of sensors (Carlyle, 1989) 25
2.11 AE sensor of the piezoelectric element (Grosse,
2008) 26
2.12 Responses of (a) resonant sensor, (b) broadband
sensor (Carlyle, 1989) 28
2.13 (a) Stress-strain diagram of a typical ductile
material; (b) determination of yield strength by the
offset method (Ugural, 2003) 30
2.14 Stress-strain curve in brittle material (Amitrano,
2003) 31
2.15 Stress versus strain along with AE energy (Aad,
xii
2015) 31
2.16 Stress versus strain along with AE RMS for AISI
type 304 stainless steel (a) annealed and (b) cold
worked 10% (Mohammadi, 2015) 32
2.17 A pressure vessel under test using AE sensors
(Parmar, 2012) 33
2.18 Linear source location 35
2.19 Two-dimensional source location (Mohd Hafizi,
2010) 36
2.20 Use of guard sensors (Hegi, 2005) 40
2.21 AE classification in terms of intensity (vertical
axis) and activity (Horizontal axis) (Aygün, 2011) 43
2.22 Typical relationships among the crack safety
index, crack growth rate, Count rate and ΔK for
bridge steels (Kaphle, 2014) 44
2.23 Assessment chart proposed by NDIS (Aygün,
2011) 45
2.24 Severity- historic index chart for analysis of
concrete bridges (Ziehl, 2008) 47
2.25 Typical intensity chart for metal piping system
(Finlayson, 2003) 48
2.26 Loading curves of a reinforced concrete beam
with corresponding Ib-Values (Shiotani, 2007) 52
2.27 Changes in Ib-value against uniaxial compressive
stress (0–100% failurestress) at various stages of
loading of granite (Rao, 2005) 53
3.1 Research flow chart 57
3.2 Typical AE system setup (Pollock, 1989) 58
3.3 ISR6 sensor 59
3.4 The AE system instrumentation setup in research
(UTM vibration lab) 60
3.5 Pencil lead test setup (UTM vibration lab) 62
3.6 The signal waveform collected from pencil lead
xiii
fracture test at 1st location (a) and at 8th location
(b); the waveform amplitudes decreasing with
distances from pencil lead fracture location and
the sensor.
63
3.7 Linear source location 66
3.8 Waves recorded by sensors 1,2 to finding TOA 67
3.9 Two dimensional source location (Nivesrangsan et
al., 2007) 68
3.10 Experimental setup – concrete plane with three
sensors (Figure not in scale) 70
4.1 Linear source location 73
4.2 Received AE signals in pencil lead test 75
4.3 Source localization results using TOA method 77
xiv
LIST OF APPENDIX
APPENDIX NO. TITLE PAGE
A Matlab Cod Localization Sources 90
1
CHAPTER 1
INTRODUCTION
1.1 Introduction
The Nondestructive testing (NDT) techniques were widely applied to detect
the internal situation of materials and structures. The link between physics and other
applied sciences promote the development of the NDT techniques. When it comes to
the classifications of the NDT techniques, they include but are not limited to acoustic
emission technique, infrared/thermal testing, visual inspection, penetrating testing,
magnetic particle testing, electromagnetic or eddy current testing, radiography, and
ultrasonic testing.
All of these non-destructive testing approaches can work individually;
however, more efficiently if multiple NDTs are employed in the meantime. It is
favorable to apply the NDT techniques into heavy industry like power plants,
aerospace and aircraft industry, leakage detection of pipelines, damage inspection of
dams, construction and maintenance of bridge structure, to name a few (Shiotani,
Aggelis et al., 2007). This research principally discussed the utilizations of the
Acoustic Emission (AE) technique in concrete damage detection.
Once the elastic wave is generated, it then travels throughout the material and
can be detected at considerable distances from its point of origin. Traveling from its
source to the point of detection, the wave is subjected to all the characteristics and
variations of its acoustic path. Its energy is attenuated by geometric spreading and
scattering by both microscopic and macroscopic variations in the material‟s structure.
2
Other kinds of attenuations may also be present. The wave‟s frequency content is
generated by the source and modified as it travels the acoustic path. The primary
information carried by the wave is the time of arrival and the elastic energy detected
at each sensor on the structure. The excitation of a sensor indicates that something
happened in the specimen at a specific time, while the amplitude indicates the level
of the disturbance. The apparent location of the source and all other characteristics
of the detected signal are modified by the characteristics of the wave‟s path to each
sensor as well as the characteristics the sensor. As a result, in a highly controlled
laboratory experiment, a reasonable estimate can be made of the characteristics of the
emission source; however, in a test on an actual structure, we are limited to what are
basically statistical estimates from multiple emissions to tell us what is happening in
the specimen. Statistical analysis is not generally used in the study of acoustic
emissions, but the state of the specimen and the location coordinates of the sources
are inferred from averages of calculated values from multiple emissions.
1.2 Problem Statement
The loss of signal amplitude when AE signals transmit through the material.
It is a common phenomenon, which has been witnessed in the AE technique test.
The amplitude of AE signals will decline rapidly in the material with high
attenuation. Attenuation dampens a stress wave as the wave front propagates away
from its source and spreads over a larger volume. Attenuation of a stress wave in an
infinite medium causes the wave amplitude to decrease proportional to the distance
from the wave source.
The concrete has unique characteristics due to heterogeneity, porosity and
presence of cracks. Besides internal damping, AE waves travelling in concrete
members undergo reflection, scattering, mode conversion and diffraction, all of
which influence the propagation of stress waves. Wave attenuation limits sensor
distance, which, in turn, limits the area that can be accurately monitored by a lead
3
pencil test. Therefore, attenuation is considered as having the major influence on the
accuracy of data collected from concrete members.
1.3 Objectives of Study
1. To investigate the reliability and performance of acoustic emission
technique that used to localization the active defects in a concrete plane.
2. To prevent wave signal attenuation which effect on the acoustic emission
system.
1.4 Scope of Study
1. Experiment the range that can be measured using the defined AE sensor.
2. Test the localization capability of the defined AE sensor in concrete.
3. Analysis the data using Matlab programming.
1.5 Thesis Organization
This thesis consists of five chapters summarized as follows:
Chapter two: presents the literature review about the acoustic emission in term of
the experimental methods.
Chapter three: describes the methodology that has been used to predict the damage
location using acoustic emission technique.
4
Chapter four: provides the results of the process for the experiment speed sound
through the concrete experiment signal wave attenuation and damage source
location, where the damage location with exact damage position then with calculated
damage position.
Chapter five: summarizes the conclusion of the work and the recommendations for
the future works.
82
REFERENCES
Achenbach, J. D. (2009). Structural Health Monitoring–What is the Prescription?.
Mechanics Research Communications, 36(2), 137-142.
Amitrano, D. (2003). Brittle‐ductile Transition and Associated Seismicity:
Experimental and Numerical Studies and Relationship with the b value.
Journal of Geophysical Research: Solid Earth (1978–2012), 108(B1).
Aad, G., Abbott, B., Abdallah, J., Khalek, S. A., Abdinov, O., Aben, R., ... &
Alonso, F. (2015). Search for Higgs Boson Pair Production in the γ γ b b¯
Final State Using p p Collision Data at s= 8 TeV from the ATLAS Detector.
Physical Review Letters, 114(8), 081802.
Abdelrahman, M. (2013). Assessment of Damage in Concrete Structures Using
Acoustic Emission.
Abraham, J., Abreu, P., Aglietta, M., Ahn, E. J., Allard, D., Allekotte, I., ... &
Bonino, R. (2010). Measurement of the Depth of Maximum of Extensive Air
Showers Above 10 18 eV. Physical Review Letters, 104(9), 091101.
Asaei, S. M. S., Lau, T. L., & Bunnori, N. M. (2012). Experimental and Numerical
Verification of the Retrofitted RC Columns using FRP-A State of the Art
Review. Caspian Journal of Applied Sciences Research, 1(9), 38-55.
Chang, P. C., & Liu, S. C. (2003). Recent Research in Nondestructive Evaluation of
Civil Infrastructures. Journal of Materials in Civil Engineering, 15(3), 298-
304.
Chen, H. G., Yan, Y. J., & Jiang, J. S. (2006). Vibration-based damage detection of
Composite Wingbox Structures using Improved Hilbert-Huang Transform.
83
Key Engineering Materials, 324, 539-542.
Comolli, L., & Micieli, A. (2011). Numerical Comparison of Peak Detection
Algorithms for the Response of FBG in Non-Homogeneous Strain Fields. In
21st International Conference on Optical Fibre Sensors (OFS21) (pp.
77538F-77538F). International Society for Optics and Photonics.
Carlos, M. F. (2003). Acoustic Emission: Heeding the Warning Sounds from
Materials. ASTM Standardization News, 31(10).
Carlyle, J. M. (1989). Acoustic Emission Testing the F-111. NDT International,
22(2), 67-73.
Cuadra, J., Vanniamparambil, P. A., Hazeli, K., Bartoli, I., & Kontsos, A. (2013).
Damage Quantification in Polymer Composites using a Hybrid NDT
Approach. Composites Science and Technology, 83, 11-21.
Cao, M., & Qiao, P. (2008). Integrated Wavelet Transform and its Application to
Vibration Mode Shapes for the Damage Detection of Beam-Type Structures.
Smart Materials and Structures, 17(5), 055014.
Carpinteri, A., Lacidogna, G., & Niccolini, G. (2006). Critical Behaviour in Concrete
Structures and Damage Localization by Acoustic Emission. Key Engineering
Materials, 312, 305-310.
Carpinteri, A., Lacidogna, G., & Puzzi, S. (2009). From Criticality to Final Collapse:
Evolution of the “b-value” from 1.5 to 1.0. Chaos, Solitons & Fractals,41(2),
843-853.
Carpinteri, A., Lacidogna, G., Accornero, F., Mpalaskas, A. C., Matikas, T. E., &
Aggelis, D. G. (2013). Influence of Damage in the Acoustic Emission
Parameters. Cement and Concrete Composites, 44, 9-16.
De Oliveira, R. F. (2005). Health Monitoring of FRP using Acoustic Emission and
Fibre Optic Techniques (Doctoral dissertation, Le Mans).
Dai, K., Smith, B. H., Chen, S. E., & Sun, L. (2014). Comparative Study of Bridge
84
Management Programmes and Practices in the USA and China. Structure and
Infrastructure Engineering, 10(5), 577-588.
Daniel, I. M., Luo, J. J., Sifniotopoulos, C. G., & Chun, H. J. (1998). Acoustic
Emission Monitoring of Fatigue Damage in Metals. Nondestructive Testing
and Evaluation, 14(1-2), 71-87.
Devi, R. R., Ali, I., & Maji, T. K. (2003). Chemical Modification of Rubber Wood
with Styrene in Combination with a Crosslinker: Effect on Dimensional
Stability and Strength Property. Bioresource Technology, 88(3), 185-188.
Figueiredo, E., Figueiras, J., Park, G., Farrar, C. R., & Worden, K. (2011). Influence
of the Autoregressive Model Order on Damage Detection. Computer‐Aided
Civil and Infrastructure Engineering, 26(3), 225-238.
Finlayson, R. D., Luzio, M. A., Miller, R. K., & Pollock, A. A. (2003, August).
Continuous Health Monitoring of Graphite Epoxy Motorcases (GEM). In
NDE for Health Monitoring and Diagnostics (pp. 272-283). International
Society for Optics and Photonics.
Grosse, C. U., & Ohtsu, M. (2008). Acoustic Emission Testing. Springer Science &
Business Media.
Gorman, M. R. (1998). Some Connections between AE Testing of Large Structures
and Small Samples. Nondestructive Testing and Evaluation, 14(1-2), 89-104.
Hoell, S., & Omenzetter, P. (2014). Damage Detection in a Wind Turbine Blade
Based on Time Series Methods. In EWSHM-7th European Workshop on
Structural Health Monitoring.
Huang, M., Jiang, L., Liaw, P. K., Brooks, C. R., Seeley, R., & Klarstrom, D. L.
(1998). Using Acoustic Emission in Fatigue and Fracture Materials Research.
JOM, 50(11), 1-14.
Hamstad, M. A., O‟Gallagher, A., & Gary, J. (2001). Effects of Lateral Plate
Dimensions on Acoustic Emission Signals from Dipole Sources. Journal of
Acoustic Emission, 19, 258-274.
85
Haneef, T., Lahiri, B. B., Bagavathiappan, S., Mukhopadhyay, C. K., Philip, J., Rao,
B. P. C., & Jayakumar, T. (2015). Study of the Tensile Behavior of AISI
Type 316 Stainless Steel using Acoustic Emission and Infrared
Thermography Techniques. Journal of Materials Research and Technology.
Holford KM, R Pullin and R J Lark. (2004) Acoustic Emission Modelling of
Concrete Hinge Joint Models. J Acoustic Emission, 22, 2004, ISSN 0730-
0050, pp 166 – 172.
Huguet, S., Godin, N., Gaertner, R., Salmon, L., & Villard, D. (2002). Use of
Acoustic Emission to Identify Damage Modes in Glass Fibre Reinforced
Polyester. Composites Science and Technology, 62(10), 1433-1444.
Jin, Z., Jiang, M., Sui, Q., Zhang, F., & Jia, L. (2013, October). Acoustic Emission
Source Linear Localization Based on an Ultra-Short FBGs Sensing System.
In Asia Pacific Optical Sensors Conference 2013 (pp. 89241F-89241F).
International Society for Optics and Photonics.
Kaphle, M. R., Tan, A., Thambiratnam, D., & Chan, T. H. (2011). Review: Acoustic
Emission Technique-Opportunities, Challenges and Current Work at QUT.
Kharrat, M., Ramasso, E., Placet, V., & Boubakar, M. L. (2014). A Signal
Processing Method for Hits Detection and Separation in High AE Activity
Systems: Application to Composite Materials under Fatigue Tests. In
EWSHM-7th European Workshop on Structural Health Monitoring.
Kaphle, M., Tan, A. C., Thambiratnam, D. P., & Chan, T. H. (2012). Identification of
Acoustic Emission Wave Modes for Accurate Source Location in Plate‐Like
Structures. Structural Control and Health Monitoring, 19(2), 187-198.
Kaphle, M. R., & Tan, A. (2009). Source Location of Acoustic Emission Waves for
Structural Health Monitoring of Bridges.
Kamala, G., Hashemi, J., & Barhorst, A. A. (2001). Discrete-wavelet Analysis of
Acoustic Emissions during Fatigue Loading of Carbon Fiber Reinforced
Composites. Journal of Reinforced Plastics and Composites, 20(3), 222-238.
86
Kaphle, M. R. (2012). Analysis of Acoustic Emission Data for Accurate Damage
Assessment for Structural Health Monitoring Applications.
Kaphle, M. R., Tan, A., Thambiratnam, D., & Chan, T. H. (2011). Review: acoustic
emission technique-opportunities, challenges and current work at QUT.
Lim, J., & Kaewkongka, T. (2008, May). Leakage Evaluation of Heating Coil Tube
in Thermal Oil Boiler by using Acoustic Emission and Data Classification
Technique. In Instrumentation and Measurement Technology Conference
Proceedings, 2008. IMTC 2008. IEEE (pp. 1659-1662). IEEE.
Lovejoy, S. C. (2008). Acoustic Emission Testing of In-service Conventionally
Reinforced Concrete Deck Girder Superstructures on Highway Bridges (No.
FHWA-OR-RD-09-05).
Mancini, S., Tumino, G., & Gaudenzi, P. (2006). Structural Health Monitoring for
Future Space Vehicles. Journal of Intelligent Material Systems and
Structures, 17(7), 577-585.
Mohammadi, R., Saeedifar, M., & Fotouhi, M. (2015). Determination of Fracture
Toughness of Heat Treated AISI D2 Steel using Finite Element and Acoustic
Emission Methods. Modares Mechanical Engineering, 14(11).
Mohd Hafizi, Z. (2010). A Study Of Acoustic Emission Intensity Effect During Fuel
Injector Fault.
Maslouhi, A. (2011). Fatigue Crack Growth Monitoring in Aluminum using Acoustic
Emission and Acousto‐Ultrasonic Methods. Structural Control and Health
Monitoring, 18(7), 790-806.
Morscher, G. N., Hurst, J., & Brewer, D. (2000). Intermediate‐Temperature Stress
Rupture of a Woven Hi‐Nicalon, BN‐Interphase, SiC‐Matrix Composite in
Air. Journal of the American Ceramic Society, 83(6), 1441-1449.
Micheletto, R., Fukuda, H., & Ohtsu, M. (1995). A Simple Method for the
Production of a Two-Dimensional, Ordered Array of Small Latex Particles.
Langmuir, 11(9), 3333-3336.
87
Nair, A., & Cai, C. S. (2010). Acoustic Emission Monitoring of Bridges: Review and
Case Studies. Engineering Structures, 32(6), 1704-1714.
Nor, N. M., Bunnori, N. M., Ibrahim, A., Shahidan, S., & Saliah, S. M. (2011,
March). An Investigation on Acoustic Wave Velocity of Reinforced Concrete
Beam In-Plane Source. In Signal Processing and its Applications (CSPA),
2011 IEEE 7th International Colloquium on (pp. 19-22). IEEE.
Nair, A., & Cai, C. S. (2010). Acoustic Emission Monitoring of Bridges: Review and
Case Studies. Engineering Structures, 32(6), 1704-1714.
Nivesrangsan, P., Steel, J. A., & Reuben, R. L. (2007). Source Location of Acoustic
Emission in Diesel Engines. Mechanical Systems and Signal Processing,
21(2), 1103-1114.
Oh, H., Azarian, M. H., & Pecht, M. (2011, May). Estimation of Fan Bearing
Degradation using Acoustic Emission Analysis and Mahalanobis Distance. In
Proceedings of the Applied Systems Health Management Conference (pp. 1-
12).
Oost, T. K., Sun, C., Armstrong, R. C., Al-Assaad, A. S., Betz, S. F., Deckwerth, T.
L., ... & Fesik, S. W. (2004). Discovery of Potent Antagonists of the
Antiapoptotic Protein XIAP for the Treatment of Cancer. Journal of
Medicinal Chemistry, 47(18), 4417-4426.
Ozevin, D., Greve, D. W., Oppenheim, I. J., & Pessiki, S. (2004, July). Resonant-
Type MEMS Transducers Excited by Two Acoustic Emission Simulation
Techniques. In Smart Structures and Materials (pp. 239-249). International
Society for Optics and Photonics.
Pandey, A. K., Biswas, M., & Samman, M. M. (1991). Damage Detection from
Changes in Curvature Mode Shapes. Journal of Sound and Vibration, 145(2),
321-332.
Rens, K. L., Nogueira, C. L., & Transue, D. J. (2005). Bridge Management and
Nondestructive Evaluation. Journal of Performance of Constructed Facilities,
88
19(1), 3-16.
Rose, J. L. (2004). Ultrasonic Waves in Solid Media. Cambridge University Press.
Ramadan, S., Gaillet, L., Tessier, C., & Idrissi, H. (2008). Assessment of the stress
Corrosion Cracking in a Chloride Medium of Cables Used in Prestressed
Concrete Structures by the Acoustic Emission Technique. Measurement
Science and Technology, 19(11), 115702.
RILEM Technical Committee. (2010). Recommendation of RILEM TC 212-ACD:
Acoustic Emission and Related NDE Techniques for Crack Detection and
Damage Evaluation in Concrete*. Materials and Structures, 43(9), 1183-
1186.
Rao, M. V. M. S., & Lakshmi, K. P. (2005). Analysis of b-value and Improved b-
Value of Acoustic Emissions Accompanying Rock Fracture. Current Science-
Bangalore-, 89(9), 1577.
Raghu Prasad, B. K., & Vidya Sagar, R. (2008). Relationship between AE Energy
and Fracture Energy of Plain Concrete Beams: Experimental Study. Journal
of Materials in Civil Engineering, 20(3), 212-220.
Ryan, T. J., Antman, E. M., Brooks, N. H., Califf, R. M., Hillis, L. D., Hiratzka, L.
F., ... & Smith, S. C. (1999). 1999 Update: ACC/AHA Guidelines for the
Management of Patients With Acute Myocardial Infarction: Executive
Summary and Recommendations A Report of the American College of
Cardiology/American Heart Association Task Force on Practice Guidelines
(Committee on Management of Acute Myocardial Infarction). Circulation,
100(9), 1016-1030.
Shiotani, T., Aggelis, D. G., & Makishima, O. (2009). Global Monitoring of Large
Concrete Structures using Acoustic Emission and Ultrasonic Techniques:
Case Study. Journal of Bridge Engineering, 14(3), 188-192.
Sagar, R. V. (2009). An experimental Study on Acoustic Emission Energy and
Fracture Energy of Concrete. In National Seminar & Exhibition on Non-
89
Destructive Evaluation (pp. 225-228).
Song, H. W., & Saraswathy, V. (2007). Corrosion Monitoring of Reinforced
Concrete Structures-A. Int. J. Electrochem. Sci, 2, 1-28.
Trujillo, B., Zagrai, A. N., Meisner, D., & Momeni, S. (2014, March). Monitoring of
Acoustic Emission Activity using Thin Wafer Piezoelectric Sensors. In SPIE
Smart Structures and Materials+ Nondestructive Evaluation and Health
Monitoring (pp. 906418-906418). International Society for Optics and
Photonics.
Ugural, A. C., & Fenster, S. K. (2003). Advanced Strength and Applied Elasticity.
Pearson Education.
Yoon, D. J., Weiss, W. J., & Shah, S. P. (2000). Assessing Damage in Corroded
Reinforced Concrete using Acoustic Emission. Journal of Engineering
Mechanics, 126(3), 273-283.
Yang, L., Zhou, Y. C., Mao, W. G., & Lu, C. (2008). Real-time acoustic emission
Testing Based on Wavelet Transform for the Failure Process of Thermal
Barrier Coatings. Applied Physics Letters, 93(23), 231906.
Ziehl, P. H. (2008, March). Applications of acoustic emission evaluation for civil
infrastructure. In The 15th International Symposium on: Smart Structures and
Materials & Nondestructive Evaluation and Health Monitoring (pp. 69340I-
69340I). International Society for Optics and Photonics.