Journal of AE, Volume 23, 2005 (ca. 43 MB) - AEWG

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Unloaded 0.9% 1.00% 1.20% 1.60% 2.00%Fig. 6 Crack development for the model sandwich composite tested in course direction (90 ° ).Applied strains are indicatedrepresented by A, where the yarns are joined together (crossover). All these sites coalesce topropagate the cracks along the sample perpendicularly to load direction by running on the sidesor legs of the loops.A2 mmFig. 7 Schematic diagram showing crack development for the model sandwich laminate with thefabric layer in the 0 ° direction (Course).In Fig. 8 the crack density can be seen and compared. In wale direction crack initiation occursat a strain of 0.85% (pre-damage) although a significant increase in crack density occursafter a strain of 1.1%. The crack initiation strain of 0.9 % is in reasonable agreement with thestrain to failure of a single layer of knitted fabric reinforced resin tested alone, which was foundto be 0.87%. In Fig. 8 it is noticed that the crack density increases in a course direction samplemore rapidly than in samples tested at wale direction. This is due to the transversal branched-likematrix cracks that grow almost randomly along the sample showing no steady section in thecurve.In order to visualize the damage initiation detected by AE signals, data from crack densitywas plotted against the AE event count rate. Thus, it is possible to observe in Fig. 9, for the sampletested on the wale direction, that the first AE signal appearing before the main cracking damage(just before 1% strain) suggesting that a lower values of strain a kind of micro-damage is30
detected (i.e. interfacial debonding). On the other hand, Fig. 10 confirm this statement since AEsignal is located before the initiation of significant cracks at 0.85% strain when the sample isloaded to the course direction.1/2s mm-1Crack density for samples at course and wale directions1.61.41.210.80.60.40.200 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3Strain (%)Course WaleFig. 8 Crack density vs. strain for sandwich composites.Model material in wale direction (0 o )Crack density vs. AE event countAE event count rate807010.9600.80.7500.6400.5300.4200.30.2100.1000 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4Strain (%)1/2s mm-1Fig. 9 AE event count rate vs. crack density loaded in wale direction.Typical stress-strain curves for samples with the wale and course direction of the fabric areshown in Figs. 11 and 12 for a commercial material, made of 5 knitted layers by RTM process,which was tested in order to compare the behavior of a model material with a commercial composite.In this case, Derekane vinyl ester was used as matrix. In general, the stress-strain curvesappear non-linear from even very small strains. Overall, the curves show a remarkable similarityto the stress-strain curves of ductile metals. Indeed, they even show a zero “work-hardening rate”region above a strain of 1.7%, with failure at 2%. In these opaque RTM materials, it was impossibleto determine the onset of cracking visually and the AE technique was used to monitor damage.AE activity is shown together with the stress-strain curves. AE activity begins at quite low31
Page 2 and 3: JOURNAL OF ACOUSTIC EMISSIONVOLUME
Page 4 and 5: 23-196 AE AND ELECTROCHEMICAL NOISE
Page 6 and 7: Volume 23 (2005) AUTHORS INDEXA. AN
Page 10 and 11: MEETING CALENDAR:The 49 th Meeting
Page 12 and 13: code [3-5]. The level of numerical
Page 14 and 15: 0.6(a)Amplitude, pm0-0.60 0.3 0.6 0
Page 16 and 17: 10S/N 1 to 20-1010S/N 1 to 1Displac
Page 18 and 19: Examination of the results in Table
Page 21: Based on the results in Table 6, we
Page 24 and 25: Fig. 7 Signal and WT of the signal.
Page 26: Then the absolute value differences
Page 29 and 30: two modes not being the same and bo
Page 31 and 32: 14. Comparison of Results with the
Page 36 and 37: understand the similitude on damage
Page 39: curve. During loading in this direc
Page 43 and 44: RTM material in course direction (9
Page 45 and 46: detected, at higher strain values t
Page 47 and 48: ACOUSTIC EMISSION DETECTION OF IMPA
Page 49 and 50: detected from this foam impact even
Page 51: Foam impact tests were also perform
Page 55 and 56: Fig. 10 Key components of the Shutt
Page 57 and 58: MOMENT TENSORS OF IN-PLANE WAVES AN
Page 59 and 60: equired. So far, numerical solution
Page 61 and 62: Fig. 4 (a) Shear dislocation model,
Page 63 and 64: plate-like sample. In this case, th
Page 65 and 66: 3. IN-PLANE THEORETICAL WAVEFORMS3.
Page 67 and 68: Fig. 11 Source model of out-of-plan
Page 69 and 70: Fig. 13 Slit model for a defect (di
Page 71 and 72: the large events, of which first ar
Page 73 and 74: Fig. 18 Crack orientations for shea
Page 75 and 76: the precise control of the gap leng
Page 77 and 78: 3. Design and Fabrication of the Se
Page 79 and 80: Fig. 7: Interferometeric pattern fo
Page 81 and 82: Fig. 9: Trace and power spectral de
Page 83 and 84: 2. Optical Fiber AE Sensor SystemA
Page 85 and 86: Fig. 4 Detected waves by the develo
Page 87 and 88: Fig. 10 Sensitivity distribution of
Page 89 and 90: Fig. 14 Experimental setup for dete
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HIGH PRECISION GEOPHONE CALIBRATION
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Fig. 3 Geophone response.the amplit
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Fig. 11 Imagenary short circuit.Fig
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Re22S0 12 0m0 0Z1= r +(14)222( )
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from G3. A geophone shakes the enti
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DEVELOPMENT OF HEAT-RESISTANT OPTIC
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2. Experiments2.1 Optical Fiber Sen
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Fig. 7 Detected quasi-AE waves.Fig.
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2. Outline of Damage Detection Syst
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Fig. 5 Outline of specimen (RN47) a
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2) The damage index transmitted fro
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microscopy [e.g., 1] or optical mic
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MPa. Under these conditions, a rock
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3. Damage Model Based on Sub-Critic
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in a positive relation. The larger
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well by the theoretical model consi
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MEASUREMENT OF HYDRAULICALLY ACTIVA
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Fig. 1 Source locations of induced
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P C means the increase of fluid pre
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A MODELING METHOD ON FRACTAL DISTRI
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as constant, Eight sensors were sel
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The number of AE events tends to de
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Fig. 10 Plan view of longwall minin
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Fig. 14 Crack distribution model of
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INTERPRETATION OF RESERVOIR CREATIO
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Fig. 2: Pumping data during the fir
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4. Focal MechanismWe observed the p
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AcknowledgementsThe seismic monitor
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Fig. 1 Arrangement of AE sensors an
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surface crack. Relations between AE
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4. ConclusionThe traces of the surf
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2. Sliding Experiments Using a Rock
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AE events accompanying sliding were
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though a limited number of m-values
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indicator for the contact state of
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2. Experimental Procedures2.1 Prepa
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Fig. 4 AE generation behavior and c
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1) The crack growth behavior under
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Fig. 1 AE monitoring system for cyc
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Fig. 4 (a) Surface photograph of in
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Fig. 8 Depth at lateral crack initi
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µm from the surface. This depth ag
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Fig. 1Conceptofthisstudy.following
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(b) By comparing the features in th
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ange K. From this result, it is und
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Figure 9 shows the relationship bet
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ACOUSTIC EMISSION BEHAVIOR OF FAILU
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Fig. 1. Statistical result of stren
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The AE signals indicating the onset
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occurrence of individual mechanisms
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ROLLING CONTACT FATIGUE DAMAGE OFWC
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and by 1.8 dB at 1 MHz. Without the
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Fig. 7 Sectional view of grooves at
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The analyzed locations are distribu
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BORON EFFECTS ON AE EVENT RATE PEAK
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Fig. 1 Stress-strain curves, AE eve
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Fig. 4 Relation between AE active s
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(2) Boron has a large strengthening
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produced during loading. Indentatio
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Fig. 3 Typical AE waveforms detecte
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formation. Thus, the crack morpholo
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Fig. 11 Examples of RD-type ENs wit
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(4) R. Ikeda, Y. Hayashi, M. Takemo
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averaged over a certain duration. O
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Fig. 3 Wavelet transform of continu
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Parameters used in time-series anal
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a minor contribution, but keeps the
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PRECURSOR OF HYDROIGEN INDUCED GLAS
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Table 1 Acoustic and elastic proper
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Fig. 5 Surface and transverse sketc
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Fig. 9 Chipped glass lining and sou
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ground coat. Crack volume and rise
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Figure 1 shows a schematic image of
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According to this process, the loca
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Fig. 5 Orientation dependence of th
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Fig. 9 Example of detected AE signa
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INVESTIGATION ON AE SIGNAL/NOISE PR
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Fig. 2 History of AE hit rates (upp
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Fig. 6 Source location of AE data i
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Fig. 9 Amplitude (upper) and hit ra
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Fig. 12 Amplitude (upper) and hit r
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EXAMINATION OF AE WAVE PROPAGATION
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Fig. 3 Waveguide for in water AE so
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and the rest through water, the obs
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INTEGRITY EVALUATION OF GLASS-FIBER
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Fig. 2 Deformation of GFRP vessel w
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Fig. 6 Load-deflection curves and c
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3.1 Test Vessels and Experimental P
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Fig. 12 Typical AE waves for vessel
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Fig. 15 Correlation between AE dura
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Fig. 1. Railway concrete piers to b
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Fig. 4 Arrangement of AE sensors wi
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5.2 Acoustic EmissionFig. 7 Develop
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Fig. 9 AE sources in three-dimensio
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Fig. 13 Amplitude distributions in
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4) T. Yasuda, S. Taniguchi, S. Kame
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Fig. 1 Water leakage in a joint sec
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A-FRQ(kHz)800600400200Normal Sectio
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ACOUSTIC EMISSION FOR FATIGUE DAMAG
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Fig. 3 Group velocity dispersion cu
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thick flange as shown in Fig. 8. Th
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Fig. 13 Relationship between load P
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PLASTIC REGION BOLT TIGHTENING CONT
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3. Experimental Results3.1 Result f
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4. Discriminant AnalysisMany noise
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Fig. 13 Cumulative AE counts select
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intra-grain mechanism, can also tak
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(a)(b)(c)(d)Fig. 4 AEsignals during
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where (σ - σ y ) is the decrease
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AN ACOUSTIC EMISSION TEST SYSTEM FO
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Fig. 1 Oxygen cylinder test system.
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5. Sensor FixtureThe sensor fixture
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Fig. 5 A block diagram of the test
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10. Experimental ResultsSeventy-one
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3. There was no indication at all o
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such modulated waveforms is difficu
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temperature distribution of the sam
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4.2 AE BehaviorFigure 4 shows a typ
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elatively low densification range.
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analysis applied for the evaluation
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• AE hits (Patterns) in the same
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3. Limitations, Errors and Classifi
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friction at the time just before th
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5. Pressure Spheres-AE/PR Case Stud
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6. Reactor Cool-Down - AE/PR Case S
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THE ACOUSTIC EMISSION HALON 1301 FI
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adius of the sphere). This definiti
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Second: any test, which did not det
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Fig. 3 Distribution of located even
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The spacing between the clusters on
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This test is included as the system
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Journal of AE, Volume 23, 2005 (ca. 43 MB) - AEWG

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