Understanding Acoustic Emission Testing- Reading 1 Part B-A

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Ultrasonic and acoustic emission testing contrasted An arbitrary mechanical excitation applied to a plate will generate a multiplicity of Lamb waves carrying energy across a range of frequencies. Such is the case for the acoustic emission wave. In acoustic emission testing, the challenge is to recognize the multiple Lamb wave components in the received waveform and to interpret them in terms of source motion. This contrasts with the situation in ultrasonic testing, where the first challenge is to generate a single, well-controlled Lamb wave mode at a single frequency. But even in ultrasonic testing, mode conversion takes place when the generated Lamb wave interacts with flaws, so the interpretation of reflected signals compounded from multiple modes becomes a means of flaw characterization. Plate or Lamb waves are similar to surface waves except they can only be generated in materials a few wavelengths thick. Charlie Chong/ Fion Zhang
2.2.5 Rayleigh Characteristics Rayleigh waves are a type of surface wave that travel near the surface of solids. Rayleigh waves include both longitudinal and transverse motions that decrease exponentially in amplitude as distance from the surface increases. There is a phase difference between these component motions. In isotropic solids these waves cause the surface particles to move in ellipses in planes normal to the surface and parallel to the direction of propagation – the major axis of the ellipse is vertical. At the surface and at shallow depths this motion is retrograde 逆行 , that is the in-plane motion of a particle is counterclockwise when the wave travels from left to right. http://en.wikipedia.org/wiki/Rayleigh_wave 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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16.7.8 Thermal Cracking Relatively
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They found that acoustic emissions
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Corrosion of Reinforcing Steel in C
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Page 169 and 170: Concrete Structures- The Troll A pl
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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
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Page 207 and 208: Attenuation: 1. Spread (30% for 2D,
Page 209 and 210: Teflon shoe http://www.ndt.net/ndta
Page 211: Lamb waves in acoustic emission tes
Page 215 and 216: Q29: The longitudinal wave incident
Page 217 and 218: The major axis of the ellipse is pe
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Page 221 and 222: Surface wave has the ability to fol
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Page 229 and 230: Other Reading: Rayleigh Waves Surfa
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Page 233 and 234: Q192: Surface waves are reduced to
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Page 241 and 242: When guided in layers they are refe
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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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Page 259 and 260: Schematic Diagram of a Basic Four-c
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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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