• Title, Summary, Keyword: Acoustic Emission(AE)

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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.

Thermo-Acoustic Emission Behavior of Composites (복합재료의 열-음향방출거동)

  • 김영복;우성충;최낙삼
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.111-115
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    • 2001
  • Thermo-acoustic emission (AE) from composite laminates under the repetitive thermal cyclic loads have been quantitatively analyzed in consideration of AE source mechanisms. The repetitive thermal load brought about a large reduction, i.e. an exponential decrease in AE total ringdown counts and AE amplitudes. It was thought that generation of thermo-AE during the first thermal cycle was not caused by crack propagation but by secondary microfracturing due to abrasive contact between crack surfaces.

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Experimental Analysis of Chatter Vibration and Acoustic Emission of Cutting Tool (절삭공구의 채터진동과 음향방출과의 실험적 연구)

  • 이종길
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.1
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    • pp.112-122
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    • 1995
  • 본 연구에서는 절삭공구가 채터진동을 일으킬때 AE(Acoustic Emission) 신호와 어떤관계가 있는지를 실험적으로 연구하였다. 모달분석을 통하여 절삭공구의 고유진동수 및 모우드형상을 구하였으며, 실제 절삭실험에서는 이송방향 및 절삭방향의 가속도를 계측하여 위상치를 결정하었다. AE신호와 두 가속도 와의 관계를 알기위하여 AE 실험을 하였다. AE신호의 폭발점은 대개 Lissajous loop의 방향전환점에서 관찰 되었다.

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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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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.

Location of Acoustic Emission Sources in a PSC Beam using Least Squares (최소제곱법에 의한 PSC보의 음향방출파원 위치결정)

  • Lee Chang-No
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.3
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    • pp.271-279
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    • 2006
  • Acoustic Emission (AE) technology is an effective nondestructive testing for continuous monitoring of defect formation and failures in structural materials. This paper presents a source location model using Acoustic Emission (AE) sensors in a Pre-Stressed Concrete (PSC) beam and the evaluation of the model was performed through lab experiments. 54 AE events were made on the surface of the 5m-PSC beam using a Schmidt Hammer and arrival times were measured with 7AE sensors. The source location f3r each event was estimated using least squares. The results were compared with actual positions and the RMSE (Root Mean Square Errors) was about 2cm.

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.

State Monitoring of Compressor using AE Signal in Life Test (압축기의 수명실험에서의 AE 신호를 이용한 상태감시)

  • 정지홍;강명창;노태영;이감규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.56-60
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    • 1997
  • The compressor is one of important elements in refrigeration cycle and play an important role of refrigeration efficiency and quality. This paper analyzes slides in rotary compressors for room air conditioners, monitoring using Acoustic Emission(AE) technique. Reliability of rotary compressors which are factory-tested has been evaluated through visual inspection on taking them apart after long term test, which is life test. This paper describes methods for acquisition and processing of Acoustic Emission(AE) raw signal to monitor state of rotary compressor in Life Test.

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A Basic Experiment of Head/Disk Interaction of Subambient Tri-Pad Slider by Using Acoustic Emission Test System

  • Pan Galina;Hwang Pyung;Choi Sung-Ryul
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.384-387
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    • 2003
  • The object of the present work is the analysis of head/disk interaction during start/stop and constant speed operation using acoustic emission (AE). The frequency spectrum analysis is performed using the AE signal obtained during the head/disk interaction. The FFT (Fast Fourier Transform) analysis of the AE signals is used to understand the interaction between the AE signal and the state of contact.

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Nondestructive Testing and Applications for Integrity Assessment of Power Plant Facilities by Acoustic Emission Technology - Part 1 : The Theory of Acoustic Emission Technology(I) - (발전설비 건전성평가를 위한 음향방출 비파괴검사 적용기술 - 제1편 : 음향방출 비파괴검사기술 이론(I) -)

  • Lee, S.G.
    • Journal of Power System Engineering
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    • v.9 no.1
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    • pp.5-13
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    • 2005
  • Acoustic emission(AE) is defined as the transient elastic waves thar are generated by the rapid release of energy. The advantage of AE is that very early crack growth can be detected well before a highly stressed component may fail. At present, an exact diagnosis is the most reliable means for determining the soundness of structures during power plant operations. AE monitoring has been applied successfully in power plants to determine mechanical problems, pressure vessel integrity and external valves leaks, vacuum leaks, the onset of cavitation in pumps and valves, the presence of flow(or no flow) in piping and heat exchange equipment, etc. Acoustic emission(AE) technology has recently strengthened its application base, and practitioners' understanding of the technique's fundamentals. This paper introduces the methods of a survey and assessment on AE monitoring applications in nuclear, fossil and hydraulic power plant. The main objective of this paper was to obtain information on various applications of AE technology in power plant.

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