Understanding Acoustic Emission Testing- Reading 1 Part B-A

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As a practical matter, the maximum distance between piezoelectric transducers, or between the transducers and the source of the acoustic emission event, should not be very large. Berthelot and Robert required an array of transducers arranged in a 40-cm square mesh to locate acoustic emission events reasonably accurately. They found that for ordinary concrete, with a fifth transducer placed in the center of the 40 x 40-cm square mesh, only about 40% of the events detected by the central transducer were also detected by the four transducers at the corners; with high strength concrete, this proportion increased to 60 to 70%. Rossi also found that a 40-cm square mesh was needed for a proper determination of acoustic emission events. Although more distant events can, of course, be recorded, there is no way of knowing how many events are “lost” due to attenuation. This is an area that requires much more study.
16.6.4 Specimen Geometry It has been shown that smaller specimens appear to give rise to greater levels of acoustic emission than do larger ones. The reasons for this are not clear, although the observation may be related to the attenuation effect described above. After an acoustic emission event occurs, the stress waves not only travel from the source to the sensor, but also undergo (1) reflection, (2) diffraction, and (3) mode conversions within the material. The basic problem of wave propagation within a bounded solid certainly requires further study, but there have apparently been no comparative tests on different specimen geometries. 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
Page 83 and 84: At about the same time, but indepen
Page 85 and 86: Figure 1: A cube with sides of leng
Page 87 and 88: Green also noted the Kaiser effect,
Page 89 and 90: 16.3 Theoretical Considerations Whe
Page 91 and 92: FIGURE 16.1 The two basic types of
Page 93 and 94: FIGURE 16.2 A typical acoustic emis
Page 95 and 96: FIGURE 16.3 Typical view of an acou
Page 97 and 98: 1. The total number of counts (e.g.
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: 16.6.3 Signal Attenuation The elast
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
Page 143 and 144: They found that, while the number o
Page 145 and 146: Sadowska-Boczar et al. tried to qua
Page 147 and 148: FIGURE 16.7 Within-batch variabilit
Page 149 and 150: 16.7.6 Fiber Reinforced Cements and
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/
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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
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The amount of energy released by an
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Activity of AE Sources in Structura
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Kaiser/Felicity effects Felicity ef
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Dunegan corollary states that if ac
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Comments: Emissions are observed pr
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Pseudo Sources In addition to the A
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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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Understanding Acoustic Emission Testing- Reading 1 Part B-A

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