• Title/Summary/Keyword: 진동 인텐시티

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Study on the Vibration Intensity in a Beam (보에 있어서 진동인텐시티에 관한 연구)

  • Kim, Young-Wan;Park, Byeong-Jeon
    • The Journal of the Acoustical Society of Korea
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    • v.16 no.5
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    • pp.36-42
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    • 1997
  • This paper purposes the measurement method of vibration intensity in building structure which is a method of measuring the intensity and the flow of vibration energy. We derived basic theory and measuring theory for a simple beam, and comparison of the experimental results with calculated results. As a result, according to the calculated value from acceleration distribution and the measurement result from the method of vibration intensity under the condition except near field of measurement zone. The measured results, show that this method is useful for measuring the vibration energy flow in building structure.

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Structural Intensity Analysis of Local Ship Structures Using Finite Element Method (유한요소법을 이용한 선체 국부 구조물의 진동인텐시티 해석)

  • Dong-Hwan Lee;Dae-Seung Cho
    • Journal of the Society of Naval Architects of Korea
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    • v.38 no.3
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    • pp.62-73
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    • 2001
  • The interest in evaluation of structural intensity arises for practical reasons, because net energy flow distribution offers information of energy transmission path, positions of sources, and sinks of vibration energy. In this paper, structural intensity analysis of local ship structures using finite element method(FEM) is carried out. The purpose of this analysis is to evaluate the relative accuracy according to mesh fineness. The structural intensity of unstiffened and stiffened plates varying their mesh fineness is analyzed and the results are compared with those obtained by the assumed mode method. As results, the proper mesh size in qualitative/quantitative structural intensity analysis of plate structures is proposed. In addition, the propagation phenomenon of vibration energy is investigated for the thickness-varying flat plate, L-type plate, and box-girder structures.

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Structural Intensity Analysis of Stiffened Plate Using Assumed Mode Method (Assumed Mode Method를 이용한 보강판의 진동인텐시티 해석)

  • Dae-Seung Cho;Sa-Soo Kim;Sang-Min Jung
    • Journal of the Society of Naval Architects of Korea
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    • v.35 no.4
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    • pp.76-86
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    • 1998
  • Structural intensity of plates experiencing bending vibration is analytically evaluated using the modal analysis based on assumed mode method. To evaluate the convergence of structural intensity according to the number of superposition modes, the power obtained by structural intensity integration over the closed curve containing the excitation source is compared with the power injected into plates. The erect of power reduction due to the material internal loss is evaluated using the intensity around a localized damping point, In addition, the dominant component among internal forces in the power transfer by the bending vibration of plates and the change of power flow due to stiffener are also investigated.

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Wave Analysis of Forced In-Plane Vibration of Plates (탄성파를 이용한 평판의 강제 내면전동 해석)

  • Kil Hyun-Gwon;Choi Jae-Sung;Hong Suk-Yoon
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.297-302
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    • 1999
  • 평판의 일반적인 형태의 진동을 해석하기 위해서는, 외면진동뿐만이 아니라 내면진동을 해석하여야 한다. 평판 내면진동의 경우 탄성파인 종파와 전단파의 전파에 의한 영향으로 발생하며, 진동 변위, 진동 에너지, 진동 인텐시티 등의 특성들을 이해하기 위해서는 각 파동의 영향을 분리하여 낼 필요가 있다. 내면진동을 해석하기 위하여 진동 모드법을 사용할 수 있으나, 각 파동에 의한 영향을 분리하여 낼 수가 없다. 본 논문에서는 진동장을 탄성파들에 의한 영향의 합으로 나타냄으로써, 각 파동에 의한 진동 변위, 진동 에너지, 진동 인텐시티 둥의 영향들을 분리할 수 있는 해석 방법을 제안하고자 한다. 이러한 해석 방법을 이용하여 점가진력에 의하여 강제 진동하는 평판의 내면 진동장에 대한 수치 계산을 수행하였다. 결과로써 진동 변위, 진동 에너지, 진동 인텐시티 등을 이루는 탄성파들의 기여도와 특성들을 분석함으로써 본 해석기법의 유용성을 보였다.

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Study on Measurements of the In-Plane Vibration Intensity In a Beam With a Damped End (감쇠 단을 갖는 보의 면내 진동인텐시티 측정에 관한 연구)

  • Kim Chang-Yeol;Kil Hyun-Gwon;Hong Suk-Yoon
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.7
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    • pp.371-378
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    • 2005
  • The objective or this paper is to measure the in-plane vibration intensity of a beam with a damped end that means the magnitude and direction of vibration power. Three experimental methods have been implemented to measure the in-plane vibration intensity over the beam. The first method is the accelerometer array method using two accelerometers. The second method is the frequency response function method using the only one accelerometer. The third method is the reference accelerometer method using a fixed reference accelerometer and another moving accelerometer. Those methods have been used to measure the spatial distribution of in-plane vibration intensity over the beam. The results obtained with those methods have been compared with each other. The results have been compared with an input power. It showed that the frequency response function method and the reference accelerometer method as well as the accelerometer array method can be effectively used to measure the in-plane vibration intensity in beams.

Improved Vibration Vector Intensity Field for FEM and Experimental Vibrating Plate Using Streamlines Visualization (유선 가시화를 이용한 FEM과 실험에 의한 진동판에 대한 개선된 진동 벡터 인텐시티장)

  • Fawazi, Noor;Jeong, Jae-Eun;Oh, Jae-Eung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.8
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    • pp.777-783
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    • 2012
  • Vibration intensity has been used to identify the location of a vibration source in a vibrating system. By using vectors representation, the source of the power flow and the vibration energy transmission paths can be revealed. However, due to the large surface area of a plate-like structure, clear transmission paths cannot be achieved using the vectors representation. Experimentally, for a large surface object, the number of measured points will also be increased. This requires a lot of time for measurement. In this study, streamlines representation is used to clearly indicate the power flow transmission paths at all surface plate for FEM and experiment. To clearly improve the vibration intensity transmission paths, streamlines representation from experimental works and FEM computations are compared. Improved transmission paths visualization for both FEM and experiment are shown in comparison to conventional vectors representation. These streamlines visualization is useful to clearly identify vibration source and detail energy transmission paths especially for large surface plate-like structures. Not only that, this visualization does not need many measured point either for experiment or FEM analysis.

Measurements of Vibration Intensity of a Coupled Beam (연성보의 진동 인텐시티 측정)

  • Lee, H.H.;Kim, C.R.;Kil, H.G.;Lee, Y.H.;Hong, S.Y.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.728-731
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    • 2005
  • The objective of this paper is to perform measurements of vibration intensity of a coupled beam. The propagation of flexural waves generates the out of plane vibration of the coupled beam. The longitudinal waves are generated due to the mode conversion at the structural joint of the coupled beam. The propagation of longitudinal waves generates the in plane vibration of the coupled beam. In order to identify the direction of vibrational power on the coupled beam, the in plane vibration intensity as well as the out of plane vibration intensity needs to be measured. The cross spectral method has been implemented to measure the in-plane vibration intensity as well as out of plane vibration intensity. The results shelved that the experimental method can be effectively used to measure the in-plane vibration intensity as well as the out of plane vibration intensity of coupled beams.

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Vibration Intensity Method to Detect Vibration Source of Rotary Compressor (로터리 컴프레서 진동원 검출을 위한 인텐시티 기법)

  • Kim, Heui-Cheol;Lee, Dong-Yeon;Yi, Hwa-Cho;Shim, Jae-Sool
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.8
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    • pp.3398-3405
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    • 2011
  • Vibration intensity (VI) method is used to reduce sound source generated from air-conditioning rotary compressor. Generally VI method is a good tool to find a sound source through vibration power flow. In this paper, the vibrations are measured by using the 3 uni-axial accelerometer from both the shells of the normal compressor and the fault compressor. The VI method successfully found out the sound source position on the surface of the compressor. In addition, the main noise (3kHz ~ 6.3kHz) was deminished by applying the newly designed compressor inner part which is related to the orginal noise source.

Sound Intensity Measurement in Near Field of Thin Plate Using Strain Gauge Bridge (스트레인 게이지 브리지를 이용한 얇은 평판의 근접장 음향 인텐시티 측정 방법론)

  • 김용조;김양한
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.10a
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    • pp.71-76
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    • 1996
  • 스트레인 게이지 브리지와 한개의 진동변위 탐촉자를 이용하여 평판의 근접장에서 음향 인텐시티를 측정하는 방법에 대하여 설명하였다. 또한 구조감쇠의 모델링을 통하여 음향방사파워에 대한 내부손실파워의 비를 나타내는 계수를 정의하여 내부손실파워의 정도를 평가하는 척도로 사용할 수 있음을 설명하였다. 임의의 경계조건을 가지는 평판에서 2개의 마이크로폰과 1개의 가속계를 이용하여 근사적으로 측정된 음향 인텐시티와 본고에서 제시한 방법으로 측정한 음향 인텐시티가 거의 일치함을 보이므로써 제시된 측정방법의 타당성을 검증하였다. 실험에 사용된 계(system)는 일반적인 해석에서 유체부하를 무시할 수 있는 계로 평판내부의 에너지 흐름에 비하여 외부로 방사되는 소음의 에너지 흐름이 매우 작기 때문에 평판내부의 에너지 흐름으로부터 방사되는 소음의 에너지 흐름을 알아내는 것이 매우 어려울 것으로 예상되었으나 본고에 제시된 방법으로 좋은 결과를 얻을 수 있었다. 앞으로 본 방법의 측정 오차에 대한 면밀한 고찰이 있어야 할 것이다. 그리고 평판의 내부손실이 비교적 큰 경우에 본 방법의 실험적으로 검증이 필요할 것이다. 또한 실질적인 문제에 응용되어 얼마만큼 유용한 정보를 제공할 것인가를 살펴보아야 할 것이다.

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Analysis of Vibration of a Simple Plate In a Medium-to-High Frequency Range With Power Flow Finite Element Method (파워흐름유한요소법에 의한 중고주파수 영역에서 단순 평판의 진동 해석)

  • Seo, Seong-Hoon;Hong, Suk-Yoon;Kil, Hyun-Gwon;Huh, Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.2
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    • pp.125-131
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    • 2003
  • In this paper Power Flow Finite Element Method(PFFEM) has been implemented to analyze the vibration of a plate in mid and high frequency ranges. In order to solve the vibration energy governing equation in Power Flow Analysis(PFA), The Finite Element Method(FEM) was used as a numerical tool. It allowed one to predict the distribution of displacement and Intensity in the plate vibrating at mid and high frequencies. The results were compared with the analytical solutions and the approximate FEM solutions. The comparison showed that PFFEM can be an effective tool to analyze the structural vibration in mid and high frequency ranges.