Understanding Acoustic Emission Testing- Reading 1 Part B-A

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There are a number of different ways in which acoustic emission signals may be evaluated. ■ <strong>Acoustic</strong> <strong>Emission</strong> Counting (ring-down counting) This is the simplest way in which an acoustic emission event may be characterized. It is “the number of times the acoustic emission signal exceeds a preset threshold during any selected portion of a test,” and is illustrated in Figure 16.4. A monitoring system may record: FIGURE 16.4 The principle of acoustic emission counting (ring-down counting). Charlie Chong/ Fion Zhang
1. The total number of counts (e.g., 13 counts in Figure 16.4). Since the shape of a burst emission is generally a damped sinusoid, pulses of higher amplitude will generate more counts. 2. The count rate. This is the number of counts per unit of time; it is particularly useful when very large numbers of counts are recorded. 3. The mean pulse amplitude. This may be determined by using a root-mean square meter, and is an indication of the amount of energy being dissipated. Clearly, the information obtained using this method of analysis depends upon both the gain and the threshold setting. Ring-down counting is affected greatly by the characteristics of the transducer, and the geometry of the test specimen (which may cause internal reflections) and may not be indicative of the nature of the acoustic emission event. In addition, there is no obvious way of determining the amount of energy released by a single event, or the total number of separate acoustic events giving rise to the counts. 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
Page 45 and 46: What is Crystal Twinning Crystal tw
Page 47 and 48: Crystal Twinning Charlie Chong/ Fio
Page 49 and 50: Crystal Twinning- Diagram of twinne
Page 51 and 52: AET Set-up Charlie Chong/ Fion Zhan
Page 53 and 54: Continuous type Charlie Chong/ Fion
Page 55 and 56: Discussion Subject: explains on the
Page 57 and 58: Kaiser Effect Plastic deformation i
Page 59 and 60: Felicity effect is an effect in aco
Page 61 and 62: Activity of AE Sources in Structura
Page 63 and 64: Felicity Effect - the applied load
Page 65 and 66: AE Parameters Various parameters us
Page 67 and 68: AET Advantages AE testing is a powe
Page 69 and 70: A Few Typical Applications • Dete
Page 71 and 72: Acoustic Emission Testing Advantage
Page 73 and 74: End of Reading 1 Charlie Chong/ Fio
Page 75 and 76: 16 Acoustic Emission Methods Charli
Page 77 and 78: Charlie Chong/ Fion Zhang
Page 79 and 80: Foreword: Acoustic emission refers
Page 81 and 82: 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: FIGURE 16.3 Typical view of an acou
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
Page 143 and 144: They found that, while the number o
Page 145 and 146: 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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16.8 Field Studies of Acoustic Emis
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16.9 Conclusions From the discussio
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Concrete Structures Charlie Chong/
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Concrete Structures Charlie Chong/
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Concrete Structures- The Troll A pl
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Concrete Structures- The Troll A pl
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End of Reading 2 Charlie Chong/ Fio
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1.0 Introduction Acoustic Emission
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Twinning Charlie Chong/ Fion Zhang
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Acoustic Emission is unlike most ot
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2.0 A Brief History of AE Testing A
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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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