• Title, Summary, Keyword: acoustic emission energy

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The Acoustic Emission Energy Analysis of Subambient Pressure Tri-Pad Slider

  • Pan Galina;Hwang Pyung;Xuan Wu
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.139-142
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    • 2004
  • The object of the present work is the acoustic emission energy analysis of subambient pressure tri-pad slider. Head/disk interaction during start/stop and constant speed were detected by using acoustic emission (AE) test system The frequency spectrum analysis is performed using the AE signal obtained during the head/disk interaction Natural frequency analysis was performed using Ansys program. Acoustic emission energy was calculated for the slider modes.

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Development of a Diagnostic Algorithm with Acoustic Emission Sensors and Neural networks for Check Valves

  • Seong, Seung-Hwan;Kim, Jung-Soo;Hur, Seop;Kim, Jung-Tak;Park, Won-Man
    • Nuclear Engineering and Technology
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    • v.36 no.6
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    • pp.540-548
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    • 2004
  • Check valve failure is one of the worst problems in nuclear power plants. Recently, many researches have been based on new technology using accelerometers and ultrasonic and magnetic flux detection have been carried out. Here, we have suggested a method that uses acoustic emission sensors for detecting the failures of check valves through measuring and analyzing backward leakage flow, a system that works without disassembling the check valve. For validating the suggested acoustic emission sensor methodology, we designed a hydraulic test loop with a check valve. We have assumed in this study that check valve failure is caused by disk wear or by the insertion of a foreign object. In addition, we have developed diagnostic algorithms by using a neural network model to identify the type and size of the failure in the check valve. Our results show that the proposed diagnostic algorithm with acoustic emission sensors is a good solution for identifying check valve failure without necessitating any disassembly work.

A Study on Crack Initiation Measurement of Carburized Gear Tooth by Acoustic Emission (침탄치차의 AE법에 의한 크랙발생의 계측에 관한 연구)

  • 류성기
    • Journal of the Korean Society of Safety
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    • v.9 no.4
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    • pp.11-16
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    • 1994
  • Acoustic emission technique is applied to the fatigue crack initiation in a carburized gear tooth. Acoustic emission test performed on carburized gear and three-point bending test equal to carburized gear hardness. The marked acoustic emission are detected at the early stage of crack initiation measured by a crack gauge and the final stage just before the tooth failure. The estimated acoustic emission energy rate are characteristic of the measured acoustic emission.

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Damage progression study in fibre reinforced concrete using acoustic emission technique

  • Banjara, Nawal Kishor;Sasmal, Saptarshi;Srinivas, V.
    • Smart Structures and Systems
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    • v.23 no.2
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    • pp.173-184
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    • 2019
  • The main objective of this study is to evaluate the true fracture energy and monitor the damage progression in steel fibre reinforced concrete (SFRC) specimens using acoustic emission (AE) features. Four point bending test is carried out using pre-notched plain and fibre reinforced (0.5% and 1% volume fraction) - concrete under monotonic loading. AE sensors are affixed at different locations of the specimens and AE parameters such as rise time, AE energy, hits, counts, amplitude and duration etc. are obtained. Using the captured and processed AE event data, fracture process zone is identified and the true fracture energy is evaluated. The AE data is also employed for tracing the damage progression in plain and fibre reinforced concrete, using both parametric- and signal- based techniques. Hilbert - Huang transform (HHT) is used in signal based processing for evaluating instantaneous frequency of the acoustic events. It is found that the appropriately processed and carefully analyzed acoustic data is capable of providing vital information on progression of damage on different types of concrete.

Characteristics of Cracks under Vickers Indentation in Glass Using Acoustic Emission (음향방출을 이용한 유리의 비커스 압입 균열 특성)

  • Park, H.Y.;Lee, J.K.;Park, H.I.;Lee, B.W.
    • Journal of Power System Engineering
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    • v.16 no.1
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    • pp.72-77
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    • 2012
  • Acoustic emission (AE) is known to be sensitive to fracture process and so it was expected that AE data may propose as a means of monitoring the fracture information. The aim of this study is to analyze the characteristic of AE signal emitted from glass during Vickers indentation. To observe AE characteristics by surface effect, both glass and coating glass were studied. During Vickers indentation loading, AE signal resulted from penny-like crack is detected. During Vickers indentation unloading, AE signal resulted from both radial/median crack and lateral crack is detected. In case of indentation on glass, the emission energy(${\epsilon}$) is found to be approximately proportional to the fourth power of the crack length. In case of indentation on coating glass, the emission energy(${\epsilon}$) is approximately proportional to the crack length.

Relationship between Acoustic Emission and Cutting Parameters of the Orthogonal Cutting Process (2차원 절삭과정에서의 Acoustic Emission과 절삭 파라미터 사이의 관계)

  • 최성주;강명순
    • Journal of the korean Society of Automotive Engineers
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    • v.9 no.2
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    • pp.47-57
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    • 1987
  • The objective of this study is to establish the comprehensive analytical relationship between acoustic emission and fundamental parameters of the orthogonal cutting process. The sources of acoustic emission in the orthogonal metal cutting process was identified as deformation in the shear zone and sliding friction at the chip-tool interface. The validity of this relationship is evaluated by a series of tests varing cutting speed and rake angle for A16063 tube. Strong dependence of the RMS voltage of acoustic emission on cutting speed and rake angle was observed. It was also found that the percentage contribution of AE energy at each zone for the total AE activity is constant in accordance with the change of cutting speed. The relationship between the RMS of acoustic emission and the fundamental cutting parameters was modified in order to be utilized independent of rake angle.

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Development of Acoustic Emission Monitoring System for Fault Detection of Thermal Reduction Reactor

  • Pakk, Gee-Young;Yoon, Ji-Sup;Park, Byung-Suk;Hong, Dong-Hee;Kim, Young-Hwan
    • Nuclear Engineering and Technology
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    • v.35 no.1
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    • pp.25-34
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    • 2003
  • The research on the development of the fault monitoring system for the thermal reduction reactor has been performed preliminarily in order to support the successful operation of the thermal reduction reactor. The final task of the development of the fault monitoring system is to assure the integrity of the thermal$_3$ reduction reactor by the acoustic emission (AE) method. The objectives of this paper are to identify and characterize the fault-induced signals for the discrimination of the various AE signals acquired during the reactor operation. The AE data acquisition and analysis system was constructed and applied to the fault monitoring of the small- scale reduction reactor, Through the series of experiments, the various signals such as background noise, operating signals, and fault-induced signals were measured and their characteristics were identified, which will be used in the signal discrimination for further application to full-scale thermal reduction reactor.

Acoustic Emission Characteristics of Notched Aluminum Plate Repaired with a Composite Patch (복합재 패치로 보수된 노치형 알루미늄 합금 평판의 음향방출 특성)

  • Yoon, Hyun-Sung;Choi, Nak-Sam
    • Journal of the Korean Society for Nondestructive Testing
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    • v.31 no.1
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    • pp.53-61
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    • 2011
  • Edge notched A16061-T6 aluminum was repaired with a GFRP composite patch as a function of the number of stacking, Damage progress of specimen for tension load has been monitored by acoustic emission(AE), AE energy rate, hit rate, amplitude, waveform and 1st peak frequency distribution were analyzed. Fracture processes were classified into Al cracking, Fiber breakage, Resin cracking and Delamination. Displacement of a specimen can be divided into Region I, II and ill according to acoustic emission characteristics. Region II where the patch itself was actually fractured was focused on to clarify the AE characteristics difference for the number of stacking.

Development of Diagnosis Technique for Converter Bearings by Using Acoustic Emission (음향방출기법을 이용한 전로베어링 안전진단 기술개발)

  • 박경조
    • Journal of the Korean Society of Safety
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    • v.18 no.2
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    • pp.6-15
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    • 2003
  • A method is presented for diagnosing the converter bearings by using acoustic emission. The flaking mechanism causing the large-scale bearing for furnace to flaw is investigated and a possibility of defect is verified by Finite Element method. he diagnosis logic is proposed fir detecting the flaw of a non-continuous rotating machine. It is proved that the acoustic emission energy can be used as a representative parameter for an acoustic event. Applying the method to the tilting bearings for steel mill in operation, the effectiveness of this logic is evaluated. It is shown that AE signal is generated only when the bearing is tilting, and the trend analysis can be focused upon this process.

Evaluation of Adhesive Bonding Quality by Acoustic Emission (음향방출시험에 의한 복합 재료 접합부의 비파괴평가)

  • Lee, J.O.;Lee, J.S.;Yoon, U.H.;Lee, S.H.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.16 no.2
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    • pp.79-85
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    • 1996
  • Prediction of fatigue life and monitoring of fracture process for adhesively bonded CFRP composites joint have been investigated by analysis of acoustic emission signals during the fatigue and tension tests. During fatigue test, generated acoustic emission is related to stored elastic strain energy. By results of monitoring of AE event rate, fatigue process could be divided into two regions, and boundaries of two regions, fatigue cycles of the initiation of fast crack growth, were 70-80% of fatigue life even though the fatigue life were highly scattered from specimen to specimen. The result shows the possibility of predicting catastrophic failure by acoustic emission monitoring.

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