• Title, Summary, Keyword: AE parameter

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A Study on the Correlation of Orthogonal Cutting all sorts Parameter and Acoustic Emission Signal (2차원 절삭시의 각종 파라메터와 음향 방출 신호와의 상호 관계에 관한 연구)

  • Kim, Jae-Yeol;Sim, Jae-Gi;Park, Hwan-Gyu;O, Hwan-Gyo
    • Journal of the Korean Society for Precision Engineering
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    • v.8 no.1
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    • pp.74-83
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    • 1991
  • A study on the Correlation of Orthogonal Cutting Parameter (Cutting speed, Depth of cut, Feed Rate) and Acoustic Emission Signal. It is well known that acoustic emission (AE) is the emission of elastic wave resulting from the deformation and fracture of materials. This study estabished correlation of orthogonal cutting parameter and AE signal, and researched into in-process monitoring of tool wear and failure. The results are as follow; 1. AE RMS was under the influence of cutting speed but hardly influenced by depth of cut and feed rate. 2. AE RMS was under the influence of flank wear. 3. AE count rate increased by increased cutting speed. 4. AE RMS value was rapidly increased in 130 m flank wear.

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Data-Driven Modelling of Damage Prediction of Granite Using Acoustic Emission Parameters in Nuclear Waste Repository

  • Lee, Hang-Lo;Kim, Jin-Seop;Hong, Chang-Ho;Jeong, Ho-Young;Cho, Dong-Keun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.1
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    • pp.75-85
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    • 2021
  • Evaluating the quantitative damage to rocks through acoustic emission (AE) has become a research focus. Most studies mainly used one or two AE parameters to evaluate the degree of damage, but several AE parameters have been rarely used. In this study, several data-driven models were employed to reflect the combined features of AE parameters. Through uniaxial compression tests, we obtained mechanical and AE-signal data for five granite specimens. The maximum amplitude, hits, counts, rise time, absolute energy, and initiation frequency expressed as the cumulative value were selected as input parameters. The result showed that gradient boosting (GB) was the best model among the support vector regression methods. When GB was applied to the testing data, the root-mean-square error and R between the predicted and actual values were 0.96 and 0.077, respectively. A parameter analysis was performed to capture the parameter significance. The result showed that cumulative absolute energy was the main parameter for damage prediction. Thus, AE has practical applicability in predicting rock damage without conducting mechanical tests. Based on the results, this study will be useful for monitoring the near-field rock mass of nuclear waste repository.

Study on the Fatigue Crack Behavior by the Stress Intensity Factor and AE Parameters (응력확대계수와 음향방출 변수를 이용한 피로균열 거동 연구)

  • Yoon, Dong-Jin;Jeong, Jung-Chae;Park, Phi-Lip;Kim, Ki-Bok;Lee, Seung-Seok
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.5
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    • pp.412-423
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    • 2000
  • By using the relation between stress intensity factor and AE parameter, new approach method for assessing the crack length and detectability of crack was proposed. Laboratory experiment was carried out to identify AE characteristics of fatigue cracks for compact tension specimen. The relationship between a stress intensity factor and AE signals activity as well as conventional AE parameter analysis was discussed. As a result, the features of specific parameter such as the length of crack growth the AE energy, the AE peak amplitude, and the cumulative AE hits, showed the almost same trend in their increase as the number of fatigue cycle increased. From the comparisons of peak amplitude and AE energy with stress intensity factor, it was verified that the higher stress intensity factors generated AE signals with higher peak amplitude and a larger number of AE counts. If we can get more reliable database for the relation between AE parameters and stress intensity factor, this approach will provide a good information for evaluating both the existence of crack and the minimum detectable size of crack.

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Application of Acoustic Emission Technique and Friction Welding for Excavator Hose Nipple (굴삭기용 호스 니플의 마찰용접과 음향방출기법의 적용)

  • Kong, Yu-Sik;Lee, Jin-Kyung
    • Journal of the Korean Society for Nondestructive Testing
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    • v.33 no.5
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    • pp.436-442
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    • 2013
  • Friction welding is a very useful joining process to weld metals which have axially symmetric cross section. In this paper, the feasibility of industry application was determined by analyzing the mechanical properties of weld region for a specimen of tube-to-tube shape for excavator hose nipple with friction welding, and optimized welding variables were suggested. In order to accomplish this object, friction heating pressure and friction heating time were selected as the major process variables and the experiment was performed in three levels of each parameter. An acoustic emission(AE) technique was applied to evaluate the optimal friction welding conditions nondestructively. AE parameters of accumulative count and event were analyzed in terms of generating trend of AE signals across the full range of friction weld. The typical waveform and frequency spectrum of AE signals which is generated by friction weld were discussed. From this study the optimal welding variables could be suggested as rotating speed of 1300 rpm, friction heating pressure of 15 MPa, and friction heating time of 10 sec. AE event was a useful parameter to estimate the tensile strength of tube-to tube specimen with friction weld.

Tool Life Monitoring using AE Signal in Gear Shaping (기어가공식 AE 신호를 이용한 공구수명의 감시)

  • 최성필
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.130-134
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    • 1996
  • The characteristics of AE(Acoustic Emission) signal is related to cutting conditio, tool material, and tool geometry in metal cutting. The relation between AE signal and tool life was investigated experimentally. Experiment is carried out by gear shaping and SCM 420 workpiece. AE RMS voltage were increased according totool wear. It is suggested that maximum value of AE RMS voltage is an effective parameter to monitor tool life.

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A Study on the Application of Acoustic Emission for the fatigue Test of Ship Welded Structure (선박의 용접구조 피로시험에 대한 음향방출기법의 적용 연구)

  • An, Sung-Chan;Kim, Dae-Soo;Lee, Jin-Hee;Park, Jin-Soo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.23 no.3
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    • pp.220-226
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    • 2003
  • This paper presents the result of an investigation on the application of the acoustic emission method to the monitoring of fatigue crack initiation, growth and track location in welded joints. Fatigue test was carried out for a typical fillet welded joint of ship structure. AE parameter such as ring down count was analyzed in time domain and crack locations were examined by source location and cluster option which is one of the functions of AE signal processor The usability of AE mettled was confirmed for the detection of the initiation and location of through crack.

The Monitoring of Abnormal Rotary Compressor using Acoustic Emission (AE를 이용한 회전형 압축기의 이상상태 감시)

  • 정지홍;이기용;강명창;김정석;이감규;안봉열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.328-332
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    • 1996
  • The compressor is one of important elements in refrigerator cycle and play an important role of refrigeration efficiency and quality. Therefore it is very important to monitor state of normal and abnormal compressor. In this research, technic of AE is used for monitoring abnormal rotary compressor and an AE parameter which is a most proper parameter to monitor the abnormal state of compressor is determined by signal processing, Finally, the monitoring result of rotary compressor is agreement with the result of life test.

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Real-Time Source Classification with an Waveform Parameter Filtering of Acoustic Emission Signals (음향방출 파형 파라미터 필터링 기법을 이용한 실시간 음원 분류)

  • Cho, Seung-Hyun;Park, Jae-Ha;Ahn, Bong-Young
    • Journal of the Korean Society for Nondestructive Testing
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    • v.31 no.2
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    • pp.165-173
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    • 2011
  • The acoustic emission(AE) technique is a well established method to carry out structural health monitoring(SHM) of large structures. However, the real-time monitoring of the crack growth in the roller coaster support structures is not easy since the vehicle operation produces very large noise as well as crack growth. In this investigation, we present the waveform parameter filtering method to classify acoustic sources in real-time. This method filtrates only the AE hits by the target acoustic source as passing hits in a specific parameter band. According to various acoustic sources, the waveform parameters were measured and analyzed to verify the present filtering method. Also, the AE system employing the waveform parameter filter was manufactured and applied to the roller coaster support structure in an actual amusement park.

Acoustic Emission Measurement on the Composite Material (CFRP) (복합재료 시험편에서의 AE 발생 특성에 관한 연구)

  • 최만용
    • Journal of the Korean Society of Safety
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    • v.6 no.4
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    • pp.21-27
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    • 1991
  • Acoustic Emission was monitored during tensile test and loading-holding-unloa-ding cycle test for two types (notched and unnotched) of CFRP specimens. AE activities showed that the fiber breakage during tensile tests depended upon the specimen geometry. We obtained new AE parameter such as the ration (damage ratio= AE events during unloading test / AE events during loading test) and the felicity ratio from which we investigated dynamic fracture process of CFRP specimens. The damage ratio of AE events was shown to be a good indicator to distinguish the generated fracture mechanism, such as fiber breakage and delamination. Also, ultrasonic testing results after loading-holding-unloading cycle test were good agreement with AE test results to detect defects or fiber breakage.

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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.