• Title/Summary/Keyword: Estimated Vibration Waveform

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A Development of Waveform Composition Program and Evaluation of Application on Site (파형합성 프로그램 개발 및 현장 적용성 평가)

  • Yoon, Ji-Sun;Woo, Taek-Gyu;Bae, Sang-Hoon
    • Explosives and Blasting
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    • v.27 no.1
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    • pp.38-46
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    • 2009
  • Recently, as a reduction method of vibration and noise, an electronic detonation which has an accuracy of time and a freedom of input delay time was introduced. A waveform composition program can determine a delay time and accomplish simulation under environment similar to real blast using a delay time. In this study, optimum delay time which controls vibration is obtained and real measurement vibration level is estimated by a waveform composition program.

A Study on the Evaluation of Shock Vibration by a Medium Characteristics (매질특성에 따른 충격진동평가에 관한 연구)

  • Song, Jeong-Un;Hong, Woong-Ki;Kim, Seung-Kon
    • Journal of Environmental Impact Assessment
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    • v.20 no.5
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    • pp.641-649
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    • 2011
  • The ground vibration has effect on the human body and the nearby structure. However, it was very difficult to estimate the damage of structure caused by the vibration. Especially, ground vibration must be estimated on the bottom of structure because it was made up of several mediums. In this study, it was considered about the shock vibration on medium characteristics as calculating the peak particle velocity and analysing the vibration waveform. The results are as follows : Firstly, the correlation coefficient of PPV(Peak Particle Velocity) and SD(Scaled Distance) was very high at the vertical component, which was represented to 0.991 in general ground medium and each 0.989, 0.961, 0.925 in concrete medium. And also, the vibration waveform at the vertical component was very good in all mediums. Secondly, the vibration waveform at the longitudinal component was represented to a great amplitude and phase difference in all mediums. It was considered that the vibration waveform occurred the damping when particle velocity by shock vibration was propagated through other medium. Thirdly, the vibration waveform in concrete medium was represented to variation of amplitude in the order of RC medium, NC=H medium, NC=S medium at the vertical component. It was considered that the particle velocity propagated fast when a medium have a big strength and density.

Assessment of Blast-induced Vibration for the Stability of Discontinuous Rock Mass (암반절리를 고려한 발파진동 영향평가)

  • Park, Byung-Ki;Jeon, Seok-Won;Park, Gwang-Jun;Do, Deog-Soo;Kim, Tae-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.485-492
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    • 2005
  • Since blast-induced vibration may cause serious problem to the rock mass as well as the nearby structures, the prediction of blast-induced vibration and the stability evaluation must be performed before blasting activities. Dynamic analysis has been Increased recently in order to analyze the effect of the blast-induced vibration. Most of the previous studies, however, were based on the continuum analysis unable to consider rock joints which significantly affect the wave propagation and attenuation characteristics. They also adopted pressure curves estimated by theoretical or empirical equations as input detonation load, thus there were very difficult to reflect the characteristics of propagating media. In this study, therefore, we suggested a discontinuum dynamic analysis technique which uses velocity waveform obtained from a test blast as an input detonation load. A distinct element program, UDEC was used to consider the effect of rock joints. In order to verify the validity of proposed method, the test blast was simulated. The predicted results from the proposed method showed a good agreement with the measured vibration data from the test blast Through the dynamic numerical modelling on the planned road tunnel and slope, we evaluated the effect of blast-induced vibration and the stability of rock slope.

Comparison of the Vibration Principal Stress by Experimental and Numerical Waveform (실측 파형과 수치 파형에 의한 진동주응력 비교)

  • Hong, Woong-Ki;Song, Jeong-Un;Park, Young-Min
    • Journal of Environmental Impact Assessment
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    • v.21 no.5
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    • pp.609-615
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    • 2012
  • In recent years, the development of computer technique was possible to the simulation analysis of the structure caused by ground vibration. Generally, finite element method(FEM) has been used in these structural analysis. In this study, it was calculated to the vibration energy as measuring vibration waveform, and estimated about principal stress due to medium characteristics of the ground as processing dynamic analysis by the vibration energy. The results are as follows : Firstly, the principal stress distribution in all mediums was different due to a medium condition, and the principal stress at concrete medium was represented to difference due to physical characteristics. Secondly, the principal stress by time increasing was represented to maximum amplitude within 0.03 second. And also, the principal stress after maximum amplitude was very large at concrete medium, which was considered to be formed compression or tension range at a medium boundary. Thirdly, the variation of principal stress at concrete medium was represented in the order of RC medium, NC=H medium, NC=S medium. It was considered that the vibration energy propagated fast when a medium have a big elasticity and density.

A Study on Vibration Analysis During the Slab Dismantling Using the Mechanical Dismantling Method (기계식 해체 공법을 적용한 슬래브 해체 시 발생하는 진동 해석 연구)

  • Noh, You-Song;Suk, Chul-Gi;Park, Hoon
    • Explosives and Blasting
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    • v.39 no.4
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    • pp.1-11
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    • 2021
  • In this study, the vibration data were obtained to analyze the vibration generated during dismantling of slab using the mechanical dismantling method. The obtained vibration data were classified according to the attachment device and then the waveform and dominant frequency analysis were performed. And the correlation was analyzed by the different methods of measuring the distance between the work section and the measurement point. As a result of the waveform analysis for each attachment device, there was little change in the phase of the vibration waveform and only the change in amplitude, which is the magnitude of the vibration velocity. And as a result of frequency analysis, the frequency band was lower when using a crusher method than a braker method and frequency band were close of the natural frequency of the structure to be dismantled. As a result of the correlation analysis, the separation distance was estimated a higher correlation when evaluated as the path through which the vibration propagates along the structure frame than the straight distance between the measurement point and the working section.

The Sound Noise and Vibration Analysis for HVDC System Faults (HVDC 시스템의 고장 시 소음 및 진동 분석)

  • Kim Chan-Ki;Park Jong-Kwang;Choi Young-Do;Lim Seong-Joo;Moon Hyoung-Bae
    • Proceedings of the KIPE Conference
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    • 2006.06a
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    • pp.319-322
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    • 2006
  • This paper deals with the HVDC system fault analysis and the sound noise analysis. In this paper, the reasons of the audible noise and vibration were analyzed, the fault waveform were analyzed using DTR (Digital Transient Recorder). Finally, using the fault current waveform and the vibration equation, the reason of crack of smoothing reactor support is estimated.

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The Sound Noise and Vibration Analysis for HVDC System Faults (HVDC 시스템의 고장 시 소음 및 진동 분석)

  • Kim, Chan-Ki
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.7
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    • pp.21-28
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    • 2006
  • This paper deals with the HVDC system fault analysis and the sound noise analysis. In this paper, the reasons of the audible noise and vibration were analyzed the fault waveform were analyzed using DTR (Digital Transient Recorder). Finally, using the fault current waveform and the vibration equation, the reason of crack of smoothing reactor support is estimated.

Assessment of Blast-induced Vibration Using Dynamic Distinct Element Analysis (불연속체 동해석 기법을 이용한 발파진동 영향평가)

  • Park, Byung-Ki;Jeon, Seokwon;Park, Gwang-Jun;Do, Deog-Soo;Kim, Tae-Hoon;Jung, Du-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.12 s.105
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    • pp.1389-1397
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    • 2005
  • Since blast-induced vibration may cause serious problem to the rock mass as well as the nearby structures, the prediction of blast-induced nitration and the stability evaluation must be performed before blasting activities. Dynamic analysis has been increased recently in order to analyze the effect of the blast-Induced vibration. Most of the previous studies, however, were based on the continuum analysis unable to consider rock joints which significantly affect the wave propagation and attenuation characteristics. They also adopted pressure corves estimated tv theoretical or empirical equations as input detonation load, thus there were very difficult to reflect the characteristics of propagating media. In this study, therefore, we suggested a dynamic distinct element analysis technique which uses velocity waveform obtained from a test blast as an input detonation load. A distinct element program, UDEC was used to consider the effect of rock joints. In order to verify the validity of proposed method, the test blast was simulated. The predicted results from the proposed method showed a good agreement with the measured vibration data from the test blast. Through the dynamic numerical modelling on the planned road tunnel and slope, we evaluated the effect of blast-induced nitration and the stability of rock slope.

Compensation of errors caused by resonance vibration of measurement system in impact force measurement

  • Usui, Y.;Miyazawa, S.;Sawai, N.
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.593-596
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    • 1994
  • When a force impulse acting on a massive and plex object is measured with a dynamometer, be resonant vibration of the measurement system often leads to serious inaccuracies. A more accurate measurement is obtained when the transfer function ,of the object-dynamometer system is used to compensate for the error in the dynamometer's output signal. The natural frequency and the damping coefficient of the transfer function are estimated by analyzing the waveform of the free damped vibration period after the loading of the force has ended. The residue of the system is determined such that the compensated force spectrum becomes smooth within a neighborhood of the natural frequency. The effectiveness of this signal processing method is experimentally tested on a hammer impulse, under the assumption that the hammer's high resonant frequency accurately models the problems encountered in force impact measurement. The compensation method is used to derive a improved estimate of the hammer impulse.

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Characterization of Axial Defects in Pipeline Using Torsional Guided Wave (비틀림 유도파를 이용한 배관 축방향 결함 특성 규명)

  • Kim, Young-Wann;Park, Kyung-Jo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.6
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    • pp.399-405
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    • 2015
  • In this work we use the mode decomposition technique employing chirplet transform, which is able to separate the individual modes from dispersive and multimodal waveform measured with the magnetostrictive sensor. The mode decomposition technique is also used to estimate the time-frequency centers and individual energies of the reflection, which would be used to locate and characterize axial defects. The arrival times of the separated modes are calculated and the axial defect lengths can be evaluated by using the estimated arrival time. Results from an experiment on a carbon steel pipe are presented and it is shown that the accurate and quantitative defect characterization could become enabled using the proposed technique.