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

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Crack source location by acoustic emission monitoring method in RC strips during in-situ load test

  • Shokri, Tala;Nanni, Antonio
    • Smart Structures and Systems
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    • v.13 no.1
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    • pp.155-171
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    • 2014
  • Various monitoring techniques are now available for structural health monitoring and Acoustic Emission (AE) is one of them. One of the major advantages of the AE technique is its capability to locate active cracks in structural members. AE crack locating approaches are affected by the signal attenuation and dispersion of elastic waves due to inhomogeneity and geometry of reinforced concrete (RC) members. In this paper, a novel technique is described based on signal processing and sensor arrangement to process multisensory AE data generated by the onset and propagation of cracks and is validated with experimental results from an in-situ load test. Considering the sources of uncertainty in the AE crack location process, a methodology is proposed to capture and locate events generated by cracks. In particular, the relationship between AE events and load is analyzed, and the feasibility of using the AE technique to evaluate the cracking behavior of two RC slab strips during loading to failure is studied.

A review of the application of acoustic emission technique in engineering

  • Gholizadeh, S.;Leman, Z.;Baharudin, B.T.H.T.
    • Structural Engineering and Mechanics
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    • v.54 no.6
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    • pp.1075-1095
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    • 2015
  • The use of acoustic emission (AE) technique for detecting and monitoring damages and the progress on damages in different structures is widely used and has earned a reputation as one of the most reliable and well-established technique in non-destructive testing (NDT). Acoustic Emission is a very efficient and effective technology used for fracture behavior and fatigue detection in metals, fiberglass, wood, composites, ceramics, concrete and plastics. It can also be used for detecting faults and pressure leaks in vessels, tanks, pipes, as well as for monitoring the progression of corrosion in welding. This paper reviews major research developments over the past few years in application of acoustic emission in numerous engineering fields, including manufacturing, civil, aerospace and material engineering.

A study on Quench Characteristics considering Winding Tension in Superconducting Coil using Acoustic Emission Technique (권선장력을 고려한 초전도 계자코일의 퀀치특성 및 AE 신호특성에 관한 연구)

  • 이준현;이민래;손명환;권영길
    • Progress in Superconductivity and Cryogenics
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    • v.1 no.2
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    • pp.8-14
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    • 1999
  • In this study, acoustic emission(AE) technique has been applied to detecting quench which is one of the serious peoblems to assure the integrity of superconducting coil at cryogenic temperature. The characteristics of AE parameters have been analyzed by correlating with the number of quenches, whinding tension of superconducting coil and charge rate of transport current. The quench localization was also performed using AE signals and there was also good correlation between quench current and AE parameters such as AE energy and AE events. In this study, it was confirmed that AE signals were mainly due to the conductor motion which caused by premature quenching. It was also found that optimized winding tension at superconducting coil was needed to prevent quench caused by conductor motion.

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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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Leak Detection Technique of Pressure Vessel Using Acoustic Emission Signal (음향방출 신호를 이용한 압력용기의 누설 검사기법 개발)

  • 이성재;정연식;강명창;김정석
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.4
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    • pp.95-99
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    • 2004
  • In this study, the leak detection technique of pressure vessel by using acoustic emission(AE) signal is suggested experimentally. The leak of pressure vessel is located at the welding line due to welding defects. we measured the AE signal using Rl5I sensor, and examined the AE parameters in leak condition. It is investigated that the mean value of AE signal is dependent on leak source location. So the absolute mean value of AE signal is adopted as dominant AE parameter. We proposed leak detection algorithm using AE signal mean value for monitoring the leak source location.

Acoustic Emission Source Location and Material Characterization Evaluation of Fiberboards (목재 섬유판의 음향방출 위치표정과 재료 특성 평가)

  • Ro Sing-Nam;Park Ik-Keum;Sen Seong-Won;Kim Yong-Kwon
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.3
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    • pp.96-102
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    • 2005
  • Acoustic Emission(AE) technique has been applied to not only material characterization evaluation but also on-line monitoring of the structural integrity. The AE source location technique is very important to identify the source, such as crack, leak detection. Since the AE waveforms obtained from sensors are very difficult to distinguish the defect signals, therefore, it is necessary to consider the signal analysis of the transient wave-form. In this study, we have divided the region of interest into a set finite elements, and calculated the arrival time differences between sensors by using the velocities at every degree from 0 to 90. A new technique for the source location of acoustic emission in fiberboard plates has been studied by introducing Wavelet Transform(WT) do-noising technique. WT is a powerful tool for processing transient signals with temporally varying spectra. If the WT de-noising was employed, we could successfully filter out the errors of source location in fiberboard plates by arrival time difference method. The accuracy of source location appeared to be significantly improved.

APPLICATION OF ACOUSTIC EMISSION FOR DIAGNOSIS OF QUENCH IN SUPER CONDUCTIVE MAGNET AT CRYOGENIC TEMPERATURE

  • Lee, Joon-Hyun;Lee, Min-Rae;Kwon, Young-Kin;Song, Bong-Min
    • Proceedings of the KSME Conference
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    • pp.160-165
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    • 2007
  • It is well recently recognized that quench is one of the serious problems for the integrity of superconducting magnets, which is mainly attribute to the rapid temperature rising in the magnet due to some extrinsic factors such as conductor motion, crack initiation etc. In order to apply acoustic emission(AE) technique effectively to monitor and diagnose superconducting magnets, it is essential to identify the sources of acoustic emission. In this paper, an acoustic emission technique has been used to monitor and diagnose quenching phenomenon in racetrack shaped superconducting magnets at cryogenic environment of 4.2K. For these purposes special attention was paid to detect AE signals associated with the quench of superconducting magnets. The characteristics of AE parameters have been analyzed by correlating with quench number, winding tension of superconducting coil and charge rate by transport current.

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Application of Acoustic Emission Technique for On-Line Monitoring of Quench in Racetrack Superconducting Coil at Cryogenic Environment (음향방출기법을 이용한 극저온 환경하에서 초전도 계자코일의 퀀칭탐지 적용에 관한 연구)

  • Lee, Min-Rae;Gwon, Yeong-Gil;Lee, Jun-Hyeon;Son, Myeong-Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.4
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    • pp.858-865
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    • 2000
  • It is well recently recognized that quench is one of the serious problems for the integrity of superconducting magnets, which is mainly attribute to the rapid temperature rising in the magnet due to some extrinsic factors such as conductor motion, crack initiation etc. In order to apply acoustic emission(AE)echnique effectively to monitor and diagnose superconducting magnets, it is essential to identify the sources of acoustic emission. In this paper, an acoustic emission technique has been used to monitor and diagnose quenching phenomenon in racetrack shaped superconducting magnets at cryogenic environment of 4.2K. For these purposes special attention was paid to detect AE signals associated with the quench of superconducting magnets. The characteristics of AE parameters have been analyzed by correlating with quench number, winding tension of superconducting coil and charge rate by transport current. In addition, the source location of quench in superconducting magnet was also discussed on the basis of correlation between magnet voltage and AE energy.

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.

Development of acoustic emission sensor using piezoelectric elements and monitoring system for polishing process (압전소자를 이용한 AE센서 및 연마공정 감시장치 개발)

  • 김정돈;김성렬;김화영;안중환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.560-565
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    • 2001
  • Recently, machining process monitoring technique based on AE(acoustic emission) signal is used widely and becomes very important technique in machining process for improving the efficiency and the confidence of the systems. In this study, we fabricated a cheap acoustic emission sensor and monitoring system and estimated the properties of them through comparing with commercial AE sensor systems. In addition, we evaluated the performance of the fabricated sensor in polishing process. Futhermore, we are scheduled to develop the multi-point polishing process monitoring system through fabrication of the more AE sensors and complement of the monitoring system.

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