Journal of AE, Volume 25, 2007 (ca. 26 MB) - AEWG

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applied in order to identify potential high risk areas of increased AE activity during loading. A summary of the experimental procedure and the derived results are reported and discussed herein. Comparison of the differences detected in AE behavior among the different columns as well as between the base and the 1 st floor joints is performed and the results are correlated with the applied load. Further processing of the located AE events, enabled the verification of the damage areas observed and the assessment of the building structural integrity. Experimental Set Up A nearly full-scale model simulating the structural configuration and seismic response of real-size reinforced concrete structures was constructed and tested. The structure comprised of two floors and one bay per direction, while its four columns formed pairs of unequal resistance and stiffness along the longitudinal (X) direction of the structure. The plan dimensions of the specimen structure were 3.15 x 3.85 m and the floor height was 2.30 m and 2.0 m at ground and top floor, respectively as presented in Fig. 1. To create an asymmetric structure that responds with torsion under translational ground motions, columns of one side were one-half size of those of the other side. All columns were 0.175-m wide while their depth varied from 0.175 m for the pair of columns at one side of the structure, to 0.35 m for the opposite pair. Columns were cast on spread footings anchored on the strong floor of the laboratory and were longitudinally reinforced with four 10-mm-diameter smooth (S220) bars for the columns with the smaller section, and six 10-mm-diameter bars for the larger ones. Transverse reinforcement consisted of 6-mm-diameter smooth (S220) bars placed at 200-mm apart. The beams and the slabs were heavily reinforced so that inelastic response would appear first on columns. A mean concrete strength of 22.8 MPa and 18.05 MPa was obtained on the day of testing at the ground and upper floor, respectively. X Z Y Fig. 1. Specimen layout, left, and AE sensor positions, right, (AE channels. 1-8 placed on column 1, ch. 9-16 on column 2, ch. 17-24 on column 3 and ch. 25-32 on column 4.). Prior to AE monitoring, the structure was subjected to the selected earthquake record scaled at 0.30 g. During this initial testing phase, the structure exhibited strong torsional response, 34
which - contrary to current beliefs based on simplistic analytical studies - induced larger displacements on the more flexible side of the building. Columns were subjected to biaxial flexure and exhibited damage concentrated at the base of smaller ground-floor columns, owing to the inadequate force transfer along the small bar overlapping length and slippage of vertical bars within the footing. Beams were over-reinforced – as it was common in this category of structures – and displayed no damage. Some hairline diagonal cracks were observed on the sides of the larger columns, owing to the development of torsional moments in these members, which closed after the test. Some cracks formed also at the beam-column interface due to slippage of the (smooth) column reinforcing bars within the joint. To reinstate the torsional balance, smaller columns (denoted here as columns 1 and 2) were reinforced via a 0.05-m-width concrete jacket cast from the footing to the top of the structure. The structure was excited again with the same seismic record at 0.30 g, while being monitored with AE. Fig. 2. Retrofitted structure: slab displacement (meters) at the ground and the top floor (top); slab rotation (rads) of the ground and the top floor (bottom). 35
Page 3 and 4: JOURNAL OF ACOUSTIC EMISSION VOLUME
Page 5 and 6: 25-194 ACOUSTIC EMISSION SOURCE LOC
Page 7 and 8: Volume 25 (2007) AUTHORS INDEX DIMI
Page 9 and 10: YUICHI TOMODA, 25-021 T. TOUTOUNTZA
Page 11 and 12: Notes for Contributors 1. General T
Page 13 and 14: In Memoriam H. Reginald Hardy, Jr.
Page 15 and 16: STRUCTURAL INTEGRITY EVALUATION USI
Page 17 and 18: The power-law AE behavior was recen
Page 19 and 20: sorting out the original signals, e
Page 21 and 22: Wood [36] in Australia has been usi
Page 23 and 24: One needs to appreciate the difficu
Page 25 and 26: In geotechnical applications, the p
Page 27 and 28: methods include the use of combined
Page 29 and 30: should take. Past attempts for stru
Page 31 and 32: 11. Suzuki, T., Ohtsu, M., Aoki, M.
Page 33 and 34: 40. http://en.wikipedia.org/wiki/Ma
Page 35 and 36: Abstract ACOUSTIC EMISSION TECHNIQU
Page 37 and 38: Fig. 1 Damage qualification by the
Page 39 and 40: After adding the data of a tested s
Page 41 and 42: Fig. 8 Sketch of a reinforced concr
Page 43 and 44: (3) Corrosion Process of Reinforced
Page 45 and 46: analysis. Corrosion cracking was si
Page 47: ACOUSTIC EMISSION MONITORING OF REI
Page 51 and 52: Fig. 4. Applied load (actuator 1) a
Page 53 and 54: concrete and the jacket. Visual ins
Page 55 and 56: Based on conventional analysis, AE
Page 57 and 58: 2. Experimental The model pipe syst
Page 59 and 60: pressure, respectively. This is ana
Page 61 and 62: Fig. 6: Power spectra from fast Fou
Page 63 and 64: small leaks (below 0.1 mm diameter)
Page 65 and 66: ACOUSTIC EMISSION TECHNIQUE APPLIED
Page 67 and 68: parameters in time domain and (c) m
Page 69 and 70: above the threshold level of 40 dB
Page 71 and 72: energy, i.e., high amplitude and lo
Page 73 and 74: An optical microscopy observation o
Page 75 and 76: Continuous WT (CWT) is defined as a
Page 77 and 78: Fig. 8. Typical AE waveforms, their
Page 79 and 80: followed by abrupt jumps in the det
Page 81 and 82: E. Landis (1999), “Micro-macro fr
Page 83 and 84: EVALUATION OF REPAIR EFFECT FOR DET
Page 85 and 86: Fig. 2 Sensor array for tomography
Page 87 and 88: 2 [ ] 2 k 3 9 2 2 1 f () 0 f ()
Page 89 and 90: At these depths, a complicated and
Page 91 and 92: The number of AE hits after repair
Page 93 and 94: damage indices of Calm and Load rat
Page 95 and 96: PVDF is a semicrystalline polymer,
Page 97 and 98: After these preliminary tests, the
Page 99 and 100:
of PVDF sensors does not seem to ha
Page 101 and 102:
Fig. 10. Evolution of a typical PAD
Page 103 and 104:
Fig. 17. Evolution of a typical dur
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I-G. Kim, H-Y. Lee and J-W. Kim (20
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Pencil-lead breaks are monopoles an
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Fig. 1 Displacement vs. time, sourc
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Fig. 5 Displacement vs. time, sourc
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Fig. 8 Displacement versus time for
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Fig. 10 Displacement vs. time. Sour
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Fig. 14 Signal amplitude versus tim
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To better relate these PLB and FEM
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HIGH-TEMPERATURE ACOUSTIC EMISSION
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thickness of 9 μm. The AlN element
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Fig. 5 Experimental setup for AE mo
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scales (and possibly salt cracks at
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DAMPING, NOISE, AND IN-PLANE RESPON
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The sharper resonance in Fig. 1c is
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i 2 RMS VDCC0 k BT = , g m 2 i
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ecause in-plane motion mostly produ
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4. B. Bahreyni, C. Shafai, Fabricat
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We first introduce our new quadridi
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Fig. 4 Amplitude profile as a funct
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Fig. 6 Change of room temperature (
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3) There are slight time lags in th
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Function Generator (FG) The functio
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Table 1 Results for continuous sens
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Fig. 7 pulse response XXX, filter :
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Fig. 11: Noise spectrum VS30-SIC-46
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waves propagate in a plate like str
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0.15 0 100kHz Driving pulse 10 100k
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0.45 0 100kHz Driving pulse 30 100k
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the sensor response to different fr
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CHARACTERISTICS OFACOUSTIC EMISSION
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Results and Discussion Shrinkage pr
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sapwood. Norway spruce wood consist
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most of the cells reached the fiber
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CHARACTERIZATION OF TITANIUM HYDRID
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Growth behavior of hydrides We stud
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were determined by the tensile test
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Figure 9 shows the Mode-I cracks in
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Results obtained are summarized as
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process of hydrogen destruction of
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Amplitude [dB] 60 55 50 45 40 35 30
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(Fig. 7) relative to the material a
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is shown in Table 1. Test specimens
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Fig. 4 Two types of AE signals dete
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the charging solution at 25 o C, by
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ANALYSIS OF ACOUSTIC EMISSION FROM
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nearly same waveforms for the first
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values). Most (11 of 14) of the rec
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Type-D (at 3.45 ms). In this sample
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NEURAL NETWORK BURST PRESSURE PREDI
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temperature, while the remaining se
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not properly set). This results in
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Conclusions Table 3 Summary of trai
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accurate source locations could be
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Fig. 1 Group velocities versus freq
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plane source orientation. But the l
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Fig. 9 Out-of-plane displacement vs
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Fig. 11 WTs of Fig. 8 with superimp
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Fig. 13 WTs of Fig. 10 with superim
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Table 3 At 102 kHz, WT peak arrival
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Fig. 17 Frequency of maximum WT int
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Fig. 18 Arrangement of sensors (#1,
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location calculation result that yi
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NOVEL ACOUSTIC EMISSION SOURCE LOCA
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tion resolution. It should be noted
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The specimen with numerous holes wa
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Fig. 5. Comparison of location meth
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Conclusions Delta-T source location
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Our approach This conceptual view c
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Voronoi Construction: Taking a case
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Fig. 6: Source location on a clamp
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PROBABILITY OF DETECTION FOR ACOUST
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POD is determined at the convergenc
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Fig. 2: Setup for illustrative runs
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Fig. 7: Probability of location (PO
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AE signals were filtered by high-pa
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Fig. 3 Accuracy and variations of a
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Fig. 7 Accuracy and variations of a
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eference data. The absolute values
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REAL-TIME DENOISING OF AE SIGNALS B
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600 500 400 300 200 kHz700 Frequenc
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the STFT result (Fig. 4(b)). Theref
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MONITORING THE EVOLUTION OF INDIVID
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the type of filtering, number of su
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was observed for either actuator. F
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Conclusions An experimental methodo
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the onset of pulses, consequently,
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zeros. The locations where a patter
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The reliability of the additional p
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AE MONITORING OF SOIL CORROSION OF
Page 283 and 284:
Fig. 2 Cumulative AE counts with ap
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cumulative event counts and amplitu
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AE was monitored using three types
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Our conclusion from these tests is
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measurements with an Exxon Nuclear
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equipment manufacturer), CISE (AE t
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Automatic testing of receptacles du
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The finalized standards are: • EN
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14. Tscheliesnig P., Lackner G., He
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Fig. 1. Typical high-temperature cr
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• Emission rates are much higher
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Fig. 4. Results of AE monitoring of
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examination at 2000-5000X was able
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samples extracted from the beam aft
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The relative comparison of the size
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Fig. 3. Schema of VB Application fo
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Fig. 5. Microstructural observation
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Fig. 7 AE source locations for diff
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Fig. 9 CT images and corresponding
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A.M. Brandt, G. Prokopski, J. Mater
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conducted with AE technique. The AE
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After location of the events, inter
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The transit times of the individual
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6) B. Schechinger, T. Vogel, Acoust
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greater than the available anchorag
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location uncertainty and is the roo
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Figures 4 and 5 illustrate all loca
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ig cracks form, localization of AE
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ased on magnetic induction, while i
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Fig. 3. AE sensors positioning on b
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As a further evaluation of the degr
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EARLY FAULT DETECTION AT GEAR UNITS
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Acoustic Emission Analysis at Rotat
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The fixed bearing at the beginning
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The time-frequency components of a
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Additionally, the gear test bench h
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APPLICATION OF ACOUSTIC EMISSION IN
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Measurements of the acoustic backgr
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Fig. 6. RMS for different ranges of
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which indicate the transition from
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surface condition. It has already b
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( 2 1) 2) ! kx1 ! k c ! x + c ! k (
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Fig. 6: Signal above normal and def
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DAMAGE ASSESSMENT OF GEARBOX OPERAT
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The waveform streaming can be trigg
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Extracting features using different
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The classifier was used to identify
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ASL spectral energy is further calc
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2 #_ of _ Sensors 2 2 2 ( x ) (
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Simulated Failure Plane One hundred
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It has been documented that the ini
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(a) (b) (c) (d) 95% _ 98% 98% _ 100
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IMPACT IMAGING METHOD TO MAP DAMAGE
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e) Step d) was repeated until the a
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Panel A Panel B Panel C Panel D Fig
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Journal of AE, Volume 25, 2007 (ca. 26 MB) - AEWG

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