• Title/Summary/Keyword: Vibration Measuring

검색결과 818건 처리시간 0.031초

발파진동의 예측기법과 환경규제 기준으로의 변환 연구 (A Study on the Prediction & Transformation of Blasting Vibration for Environmental Regulation Standard)

  • 김남수;양형식
    • 터널과지하공간
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    • 제11권1호
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    • pp.14-19
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    • 2001
  • 발파진동을 계측하여 예측방법의 타당성을 검토하였고, 환경규제 기준으로의 변환방식을 규명하였다. 진동레벨과 진동속도의 환산거리 설계 적용성은 진동속도가 더 좋았다. 따라서 설계나 시공은 진동속도로 관리하고 이를 법적 기준인 진동레벨로 변환할 필요성이 있었다. 기존의 변환식 중에서 충격진동 데이터로만 구성하여 변환식을 구하였고, 동시에 측정된 진동속도와 진동레벨의 상관식에 의한 변환식을 구하였으며, 퓨리에 변환을 하여 각 주파수 별로 감각보정하여 진동레벨을 구하였다. 세 가지 방법을 이용하여 변환한 결과 모두 오차가 있으므로 변환에 의한 피해 보상의 판정에는 무리가 있었으나, 그 중에서 발파시 동시에 측정된 수직방향 성분 PPV와 진동레벨의 변환식이 가장 실용적으로 판단되었다.

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Evaluating Methods of Vibration Exposure and Ride Comfort in Car

  • Park, Se Jin;Subramaniyam, Murali
    • 대한인간공학회지
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    • 제32권4호
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    • pp.381-387
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    • 2013
  • Objective: This paper studies the method of measuring whole-body vibration in the car and terms associated. Background: Human exposure to vibration can be broadly classified as localized and whole-body vibration. The whole-body vibration affects the entire body of the exposed person. It is mainly transmitted through the seat surfaces, backrests, and through the floor to an individual sitting in the vehicle. It can affect the comfort, performance, and health of individuals. Method: Human responses to whole-body vibration can be evaluated by two main standards such as ISO 2631 and BS 6841. The vibration is measured at 8 axes - three translations at feet, 3 translations of hip and two translations of back proposed by Griffin. B&K's sensors used in this study are the 3-axes translational acceleration sensor to measure the translational accelerations at the hip, back and foot. Results: The parameters associated with the whole-body vibration in the car are frequency weightings, frequency weighted root-mean-square, vibration dose values, maximum transient vibration value, seat effective amplitude transmissibility, ride values and ride comfort. Conclusion: Studied the evaluating methods of vibration exposure and ride comfort. Application: Evaluation of whole-body vibration in the car.

22.9kV 다중 접지 지중 전력 케이블의 가압 상태 진단에 관한 기초 연구 (A Study on Diagnosis of The Energized Status of 22.9kV Multigrounded Underground Power Cable)

  • 김창교;홍진수;정영호
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제48권10호
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    • pp.699-703
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    • 1999
  • An experimental study to identify the energized status of the 22.9kV underground power cable by the detection of vibration has been performed. We have derived that there exists vibration at double the line frequency in live cables by electromagnetic force. The relative amplitudes of the cable vibration according to the energized status of the cable were calculated by computer simulation. The cable vibration can also be picked up by accelerometer. A prototype was tested on the underground distribution system in Chonan substation, KEPCO. Comparison between simulation results and field test results was performed. The results showed that the energized status of the calble can be identified by measuring the vibration of the cable using accelerometer.

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VIBRATION PROPERTIES OF PEARS

  • Kim, M. S.;H. M. Jung;Park, I. K.;Park, J. M.
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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    • pp.533-542
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    • 2000
  • Instrumentation and technologies are described for determining the vibration response characteristics of the pear with frequency range 5 to 320Hz. The computer program for controlling the vibration exciter and the function generator and for measuring the vibration response characteristics of the pear was developed. Mechanical properties such bioyield deformation, rupture deformation and apparent elastic modulus etc. were compared with the vibration response characteristics of the pear. The resonant frequency of the pear ranged from 53 to 102Hz and the amplitude at resonance was between 1.08 and 2.48g-rms. The resonant frequency and amplitude at resonance decreased with the increase of the sample mass, and they were slightly affected by mechanical properties such as bioyield deformation and rupture deformation. Regression analysis was performed among the relatively high correlated parameters from the results of correlation coefficient analysis.

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A Study on the Measurement and Analysis of Whirling Vibration Behavior of Marine Propulsion Shafting System using Gap-sensors

  • Sun, Jin-Suk;Han, Tae-Min;Lee, Kang-Ki;Kim, Ue-Kan
    • Journal of Advanced Marine Engineering and Technology
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    • 제39권2호
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    • pp.130-135
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    • 2015
  • Recently, as a result of the application of large and multi-blade propellers with high efficiency for large vessels, the vertical bending stiffness of propulsion shafting system tends to be declined. For some specific vessels, the shaft arrangement leads to the forward stern tube bearing to be omitted, decreasing vertical bending stiffness. In this respect, decreased vertical bending stiffness causes the problem which is the blade order resonance frequency to be placed within the operational rpm range of propulsion shafting system. To verify whirling vibration, the measurement should be carried out covering from operating rpm up to target rpm, however, the range is un-measurable generally. In order to resolve the measurement issue, this study shows the measuring method and the assessment method of relevant natural frequency of whiling vibration by using measured harmonic order component of whirling vibration.

선박용 4행정 디젤엔진의 과도 비틀림 진동에 관할 연구 (A study on the Transient Torsional Vibrations of Four Stroke Marine Diesel Engines)

  • 이돈출;유정대;전효중
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문집
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    • pp.44-50
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    • 2002
  • Theoretical analysis on the transient torsional vibration was started from early 1960's for high power synchronous motor application. As for marine engineering, simulation and measuring techniques of transient torsional vibration have been steadily studied by manufacturer of flexible coupling and designer of four stroke marine diesel engine. In this paper, the simulation method of transient torsional vibration for four stroke marine diesel engine application using Newmark method is introduced.

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전자 광학적 훌로그래픽 간섭법을 이용한 진동물체의 모드형태 계측법 (Measurement Method of the Vibration Mode Shapes Using Electro-Optic Holographic Interferometry)

  • 최장섭;강영준
    • 대한기계학회논문집A
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    • 제20권2호
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    • pp.564-574
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    • 1996
  • This paper describes as Electronic Speckle Pattern Interferometry system which has been designed for measuring vibration patterns and quantitative measurement of vibration amplitude fields by using the time average method on a object. Visbility of fringe patterns is more improved by using the phase stepping and frame average method to reduce speckle and electric noise. And a bias vibration is introduced into the reference beam to shift the $\frac{2}{0}$ fringes so that fringe shift algorithms can be used to determine vibration amplitude. The experimental results are compared to those of the FFT analyzer and the FEM model analysis.