• 제목/요약/키워드: AE, Acoustic Emission

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

  • 윤현성;최낙삼
    • 비파괴검사학회지
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    • 제31권1호
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    • pp.53-61
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    • 2011
  • 본 연구는 편측 노치가 삽입된 A16061-T6 알루미늄 합금 평판 시편에 대해 유리섬유강화플라스틱(GFRP) 복합재 패치의 적층수를 변수로 하여 보수히고, 인장 하중에 따른 시편의 손상 과정을 음향방출법(acoustic emission, AE)으로 실시간 분석하였다. AE 에너지 발생률(AE energy rate), hit 발생률(hit rate), AE 진폭(AE amplitude) 거통과 파형 및 1차 중심주파수(1st peak frequency)의 대역을 조사하여, 시편 파괴시 알루미늄 크랙(Al cracking), 섬유 파단(fiber breakage), 수지 균열(resin cracking), 층간 분리(delamination)로 분류하였다. 시편의 변위를 음향방출 특성에 따라 구간(region) I, II, III으로 나눌 수 있었으며, 패치 자체가 실제 파괴되는 구간인 구간 II를 세부적으로 분석하여 패치의 적층수에 따른 AE 특성 차이를 구하였다.

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

  • 김영복;우성충;최낙삼
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2001년도 추계학술발표대회 논문집
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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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절삭공구의 채터진동과 음향방출과의 실험적 연구 (Experimental Analysis of Chatter Vibration and Acoustic Emission of Cutting Tool)

  • 이종길
    • 한국정밀공학회지
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    • 제12권1호
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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
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2004년도 학술대회지
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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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음향방출을 이용한 유리의 비커스 압입 균열 특성 (Characteristics of Cracks under Vickers Indentation in Glass Using Acoustic Emission)

  • 박혜연;이종규;박흥일;이병우
    • 동력기계공학회지
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    • 제16권1호
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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.

Carbon Fiber Reinforced Plastic(CFRP)복합재의 파괴 거동에 따른 Acoustic Emission(AE)신호 특성에 관한 연구 (A Study on the characteristics of the Signals of AE according to Fracture mode of CFRP)

  • 이경원;김종현;김재성;이보영
    • 한국항공운항학회지
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    • 제17권4호
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    • pp.42-47
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    • 2009
  • Recently, the wide range of the composite materials is used for the making airplanes, trains and automobiles body for the lightweight. Despite having complex structures, composite materials usually have well defined mechanical characteristics. However, composite materials are difficult to understand the fracture mechanism clearly by simple mechanical test. Nondestructive evaluation (NDE) combined with mechanical testing can play a more important role and especially Acoustic Emission Testing (AET) would become known to be a useful tool to assess damage and fracture behavior of composites. In this study The experiment was performed to acquire the acoustic emission signal during tensile test using unidirectional CFRP specimen and the data was analyzed the acoustic emission parameters with the waveform.

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

  • 이창노
    • 한국측량학회지
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    • 제24권3호
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    • pp.271-279
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    • 2006
  • 음향방출(AE: Acoustic Emission) 기법은 구조물 내부에서 발생하는 균열을 연속적으로 모니터링 할 수 있는 효과적인 비파괴검사법이다. 본 논문에서는 AE센서을 이용하여 PSC 보에서의 파원위치를 결정하기 위한 수학적 모델을 제시하고 실험을 통해 제시된 모델을 평가하였다. 실험을 위해 제작된 5m-PSC보의 표면에서 인위적으로 쉬미트해머의 타격에 의해 탄성파를 발생시켰으며 1m 간격으로 선형으로 배치된 7개의 AE센서에 의해 탄성파의 도달시간이 측정되었다. 최소제곱법에 의해 측정된 도달시간의 잔차의 제곱합이 최소가 되도록 파원의 위치를 구한 후, 실제 타격위치와 비교하여 추정된 위치결정방법의 정확도를 평가하였다. 54개의 타격실험을 통해 얻어진 파원위치의 평균제곱근 오차는 약 2cm 이었다.

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
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2003년도 학술대회지
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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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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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    • 제23권2호
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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.

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

  • 이상국
    • 동력기계공학회지
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    • 제9권1호
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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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