Understanding Acoustic Emission Testing- Reading 1 Part B-A

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Attenuation The intensity of an AE signal detected by a sensor is considerably lower than the intensity that would have been observed in the close proximity of the source. This is due to attenuation. There are three main causes of attenuation, (1) beginning with geometric spreading. As an AE spreads from its source in a plate-like material, its amplitude decays by 30% every time it doubles its distance from the source. In three-dimensional structures, the signal decays on the order of 50%. This can be traced back to the simple conservation of energy. (2) Another cause of attenuation is material damping, as alluded 指出 to in the previous paragraph. While an AE wave passes through a material, its elastic and kinetic energies are absorbed and converted into heat. (σ abs ) (3) The third cause of attenuation is wave scattering. Geometric discontinuities (e.g. twin boundaries, nonmetallic inclusions, or grain boundaries) and structural boundaries both reflect some of the wave energy that was initially transmitted. (σ scat ) Charlie Chong/ Fion Zhang
Attenuation: 1. Spread (30% for 2D, 50% for 3D for each doubling of distance from source), 2. Material damping, absorption. 3. Scattering (reflection & difrraction) 3 1 2 3 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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1. The total number of counts (e.g.
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■ Rise time — This is the inter
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Energy analysis — This is an indi
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FIGURE 16.5 The main elements of a
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Fourier-Transform (FT) The Fourier
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Signal Evaluation: Analysis of the
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Signal Evaluation: Raise Time/ Even
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Signal Evaluation: Amplitude Distri
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Signal Evaluation: Energy analysis-
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Signal Evaluation: Raise Time/ Even
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FIGURE 16.5 The main elements of a
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A brief description of the most imp
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PZT:- If the p.d or the stress is c
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AET Transducer In 0.1KHz~2.0KHz Cha
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2. Preamplifier: Because of the low
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There are generally two (or more) c
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Spooner and Dougill confirmed that
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Spooner and Dougill conclusion on K
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16.6.3 Signal Attenuation The elast
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16.6.4 Specimen Geometry It has bee
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16.6.6 Concrete Strength It has bee
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16.7.1 Fracture Mechanics Studies A
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16.7.2 Type of Cracks A number of a
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They found that, while the number o
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Sadowska-Boczar et al. tried to qua
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FIGURE 16.7 Within-batch variabilit
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16.7.6 Fiber Reinforced Cements and
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Fiber Reinforced Cements and Concre
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Perhaps the most extensive series o
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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
Page 199 and 200: Waves radiates from the source in a
Page 201 and 202: Angular dependence of acoustic emis
Page 203 and 204: The signal that is detected by a se
Page 205: highly damped, nonmetallic material
Page 209 and 210: Teflon shoe http://www.ndt.net/ndta
Page 211 and 212: Lamb waves in acoustic emission tes
Page 213 and 214: 2.2.5 Rayleigh Characteristics Rayl
Page 215 and 216: Q29: The longitudinal wave incident
Page 217 and 218: The major axis of the ellipse is pe
Page 219 and 220: Surface wave Charlie Chong/ Fion Zh
Page 221 and 222: Surface wave has the ability to fol
Page 223 and 224: Surface wave - One wavelength deep
Page 225 and 226: Rayleigh Wave Charlie Chong/ Fion Z
Page 227 and 228: Love Wave Charlie Chong/ Fion Zhang
Page 229 and 230: Other Reading: Rayleigh Waves Surfa
Page 231 and 232: Q110: What kind of wave mode travel
Page 233 and 234: Q192: Surface waves are reduced to
Page 235 and 236: Since the 1990s, the understanding
Page 237 and 238: Plate or Lamb waves are the most co
Page 239 and 240: Plate wave or Lamb wave are formed
Page 241 and 242: When guided in layers they are refe
Page 243 and 244: Symmetrical = extensional mode Asym
Page 245 and 246: Other Reading: Lamb Wave Lamb waves
Page 247 and 248: Fig. 4 Diagram of the basic pattern
Page 249 and 250: 2.2.7 Dispersive Wave: Wave modes s
Page 251 and 252: Discussion Subject: Wave Mode and V
Page 253 and 254: Key Points: • Two classes: resona
Page 255 and 256: 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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