Understanding Acoustic Emission Testing- Reading 1 Part B-A

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16.7.5 Drying Shrinkage <strong>Acoustic</strong> emission has been used to try to monitor shrinkage in cement pastes and mortars. Nadeau et al. found that, in hardened pastes, the acoustic emission resulted from cracking due to the unequal shrinkage of the hydration products. Mortar gave less acoustic emission than hardened paste, suggesting that the fracture processes at the sand/cement paste interface are not an important source of acoustic emission. Jeong et al. also suggested that, in autoclaved aerated concrete, the acoustic emissions during drying could be related to microcracking. Again, however, it is unlikely that acoustic emission measurements will be able to be used as a means of predicting the shrinkage as a function of time. Charlie Chong/ Fion Zhang
16.7.6 Fiber Reinforced Cements and Concretes A number of acoustic emission studies have been carried out on fiber reinforced cements and concretes. Lenain and Bunsell, in a study of asbestos cement, found that acoustic emissions resulted both from cracking of the matrix and fiber pullout. They noted that the Kaiser effect was not found for this type of fiberreinforced composite, since on unloading of a specimen the partially pulled out fibers were damaged, and particles of cement attached to them were crushed, giving rise to acoustic emissions on unloading. Because these damaged fibers were then less able to resist crack growth, on subsequent reloading cracks started to propagate at lower stress levels than on the previous cycle, thus, giving off acoustic emissions below the previously achieved maximum load. Akers and Garrett also studied asbestos cement; they found that acoustic emission monitoring could be used to detect the onset and development of prefailure cracking. Charlie Chong/ Fion Zhang
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Understanding Acoustic Emission Tes
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Concrete Offshore structure Charlie
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Refinery Applications Charlie Chong
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Charlie Chong/ Fion Zhang
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The Magical Book of Acoustic Emissi
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ASNT Certification Guide NDT Level
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3 Techniques • Equipment calibrat
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Fion Zhang at Shanghai 3rd Septembe
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Charlie Chong/ Fion Zhang http://gr
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Video on - Leak Detection on Buried
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ASME V Article Numbers: Gen Article
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ASTM Standards E976 - 05 Standard G
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ASTM Standards E1781 - 08 Standard
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Typical AET Signal https://dspace.l
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Study Note 1: AET http://www.geocit
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Until about 1973, acoustic emission
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Charlie Chong/ Fion Zhang http://ww
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AE Technique The AE technique (AET)
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What is Normal (Gaussian) distribut
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Probability density function for th
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Cumulative distribution function of
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Crystal Twinning Crystal twinning o
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What is Crystal Twinning Crystal tw
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Crystal Twinning Charlie Chong/ Fio
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Crystal Twinning- Diagram of twinne
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AET Set-up Charlie Chong/ Fion Zhan
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Continuous type Charlie Chong/ Fion
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Discussion Subject: explains on the
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Kaiser Effect Plastic deformation i
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Felicity effect is an effect in aco
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Activity of AE Sources in Structura
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Felicity Effect - the applied load
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AE Parameters Various parameters us
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AET Advantages AE testing is a powe
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A Few Typical Applications • Dete
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Acoustic Emission Testing Advantage
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End of Reading 1 Charlie Chong/ Fio
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16 Acoustic Emission Methods Charli
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Foreword: Acoustic emission refers
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Acoustic emissions, which occur in
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At about the same time, but indepen
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Figure 1: A cube with sides of leng
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Green also noted the Kaiser effect,
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16.3 Theoretical Considerations Whe
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FIGURE 16.1 The two basic types of
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FIGURE 16.2 A typical acoustic emis
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FIGURE 16.3 Typical view of an acou
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Page 99 and 100: ■ Rise time — This is the inter
Page 101 and 102: Energy analysis — This is an indi
Page 103 and 104: FIGURE 16.5 The main elements of a
Page 105 and 106: Fourier-Transform (FT) The Fourier
Page 107 and 108: Signal Evaluation: Analysis of the
Page 109 and 110: Signal Evaluation: Raise Time/ Even
Page 111 and 112: Signal Evaluation: Amplitude Distri
Page 113 and 114: Signal Evaluation: Energy analysis-
Page 115 and 116: Signal Evaluation: Raise Time/ Even
Page 117 and 118: FIGURE 16.5 The main elements of a
Page 119 and 120: A brief description of the most imp
Page 121 and 122: PZT:- If the p.d or the stress is c
Page 123 and 124: AET Transducer In 0.1KHz~2.0KHz Cha
Page 125 and 126: 2. Preamplifier: Because of the low
Page 127 and 128: There are generally two (or more) c
Page 129 and 130: Spooner and Dougill confirmed that
Page 131 and 132: Spooner and Dougill conclusion on K
Page 133 and 134: 16.6.3 Signal Attenuation The elast
Page 135 and 136: 16.6.4 Specimen Geometry It has bee
Page 137 and 138: 16.6.6 Concrete Strength It has bee
Page 139 and 140: 16.7.1 Fracture Mechanics Studies A
Page 141 and 142: 16.7.2 Type of Cracks A number of a
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Page 145 and 146: Sadowska-Boczar et al. tried to qua
Page 147: FIGURE 16.7 Within-batch variabilit
Page 151 and 152: Fiber Reinforced Cements and Concre
Page 153 and 154: Perhaps the most extensive series o
Page 155 and 156: 16.7.8 Thermal Cracking Relatively
Page 157 and 158: They found that acoustic emissions
Page 159 and 160: Corrosion of Reinforcing Steel in C
Page 161 and 162: 16.8 Field Studies of Acoustic Emis
Page 163 and 164: 16.9 Conclusions From the discussio
Page 165 and 166: Concrete Structures Charlie Chong/
Page 167 and 168: Concrete Structures Charlie Chong/
Page 169 and 170: Concrete Structures- The Troll A pl
Page 171 and 172: Concrete Structures- The Troll A pl
Page 173 and 174: End of Reading 2 Charlie Chong/ Fio
Page 175 and 176: 1.0 Introduction Acoustic Emission
Page 177 and 178: Twinning Charlie Chong/ Fion Zhang
Page 179 and 180: Acoustic Emission is unlike most ot
Page 181 and 182: 2.0 A Brief History of AE Testing A
Page 183 and 184: 3.0 Theory - AE Sources As mentione
Page 185 and 186: The amount of energy released by an
Page 187 and 188: Activity of AE Sources in Structura
Page 189 and 190: Kaiser/Felicity effects Felicity ef
Page 191 and 192: Dunegan corollary states that if ac
Page 193 and 194: Comments: Emissions are observed pr
Page 195 and 196: Pseudo Sources In addition to the A
Page 197 and 198: Wave Propagation A primitive wave r
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Waves radiates from the source in a
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Angular dependence of acoustic emis
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The signal that is detected by a se
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highly damped, nonmetallic material
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Attenuation: 1. Spread (30% for 2D,
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Teflon shoe http://www.ndt.net/ndta
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Lamb waves in acoustic emission tes
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2.2.5 Rayleigh Characteristics Rayl
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Q29: The longitudinal wave incident
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The major axis of the ellipse is pe
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Surface wave Charlie Chong/ Fion Zh
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Surface wave has the ability to fol
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Surface wave - One wavelength deep
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Rayleigh Wave Charlie Chong/ Fion Z
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Love Wave Charlie Chong/ Fion Zhang
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Other Reading: Rayleigh Waves Surfa
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Q110: What kind of wave mode travel
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Q192: Surface waves are reduced to
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Since the 1990s, the understanding
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Plate or Lamb waves are the most co
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Plate wave or Lamb wave are formed
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When guided in layers they are refe
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Symmetrical = extensional mode Asym
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Other Reading: Lamb Wave Lamb waves
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Fig. 4 Diagram of the basic pattern
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2.2.7 Dispersive Wave: Wave modes s
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Discussion Subject: Wave Mode and V
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Key Points: • Two classes: resona
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Q. The most common range of acousti
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Equipment- Probe Charlie Chong/ Fio
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Schematic Diagram of a Basic Four-c
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After passing the AE system mainfra
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AET Charlie Chong/ Fion Zhang
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6.0 AE Signal Features With the equ
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Amplitude, A, is the greatest measu
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7.0 Data Display Software-based AE
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Intensity displays are used to give
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Amplitude/counts Signal Analysis Th
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Source location techniques assume t
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Because the above scenario implicit
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When additional sensors are applied
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9.0 AE Barkhausen Techniques The Ba
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Hysterisis Loop- magnetization or d
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■ Bucket Truck (Cherry Pickers) I
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■ Gas Trailer Tubes Acoustic emis
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■ Aerospace Structures Most aeros
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Others • Fiber-reinforced polymer
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Study Note 4: ASTM E1316 Term & Def
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• acoustic emission (AE)- the cla
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• acoustic emission signature (si
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• array, n- a group of two or mor
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• continuous emission- see emissi
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• dB AE - a logarithmic measure o
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AE signal amplitude measured as a r
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• distribution, differential (aco
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effective velocity, n- velocity cal
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FIG. 1 Burst Emission on a Continuo
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FIG. 3 Continuous Emission. (Sweep
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examination area- that portion of a
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Kaiser effect- the absence of detec
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Linear, Planar, 3D Linear 3D Planar
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location, continuous AE signal, n-
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Methods of Location • Hit method
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logarithmic (acoustic emission) amp
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signal overload level- that level a
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stimulation- the application of a s
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End of Reading 4 Charlie Chong/ Fio
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Q1. The most common range of acoust
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Q5. The felicity effect is useful i
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Q9. Threshold settings are determin
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Q12. What is the Felicity Effect? A
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Q15. A Hsu-Nielson Source: A. measu
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Q19. The term ""rise time"" refers
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Q23. Four types of AE Source Locati
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Study Note 6: High Strength Steel-
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The properties of different steels
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Keywords: • DP (dual phase), •
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Figure 1: Ductility-strength relati
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However, with conventional TRIP ste
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Back to Basic: Martensite Martensit
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Keywords: Hexagonal & BCC Martensit
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Figure 2: The stress-strain diagram
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Also, the TRIP steel is particularl
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Figure 3: The diagram shows the ver
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Table 1: Effect of alloying element
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■ B, Ti, Zr Adding small amounts
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Acoustic Emission Technique the opt
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ASM introduction Since 1908, ASM is
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Active approach to leak detection T
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Leak detection and location The mod
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■ Method of testing (Linear) The
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Fig 2: Cross-correlation function p
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The figure 1 shows how the position
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Area surveys using acoustic loggers
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The reading of an area meter could
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CONCLUSIONS In the last fifteen yea
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■ ωσμ∙Ωπ∆ ∇ º≠δ≤
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Peach - 我爱桃子 Charlie Cho
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Good Luck Charlie Chong/ Fion Zhang
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