• Title/Summary/Keyword: Coupled vibration

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Coupled Vibration of Functionally Graded Cylindrical Shells Conveying Fluid (유체 유동을 고려한 경사기능재료 원통셸의 연성진동)

  • Kim, Young-Wann;Kim, Kyu-Ho;Wi, Eun-Jung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.11
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    • pp.1119-1125
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    • 2009
  • The coupled fluid-structure interaction problem is analyzed using the theoretical method to investigate the coupled vibration characteristics of functionally graded material(FGM) cylindrical shells conveying an incompressible, inviscid fluid. Material properties are assumed to vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. The steady flow of fluid is described by the classical potential flow theory. The motion of shell represented by the first order shear deformation theory(FSDT) to account for rotary inertia and transverse shear strains. The effect of internal fluid can be taken into consideration by imposing a relation between the fluid pressure and the radial displacement of the structure at the interface. Numerical examples are presented and compared with exiting results.

Natural Vibration Analysis of Two Circular Plates Coupled with Bounded Fluid (갇힌 유체로 연성된 두 원판의 고유진동 해석)

  • 정명조;정경훈
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.9
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    • pp.439-453
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    • 2001
  • This study deals with the free vibration of two identical circular plates coupled with a bounded fluid. An analytical method based on the finite Fourier-Bessel series expansion and Rayleigh-Ritz method is suggested. In the theory, it is assumed that the ideal fluid in a rigid cylindrical container and the two plates are clamped along the plate edges. The proposed method is verified by the finite element analysis using commercial program with a good accuracy. Two transverse vibration modes, namely in-phase and out-of-phase, are observed alternately in the fluid-coupled system when the number of nodal circles increases for the fixed nodal diameter. The effect of gap between the plates on the fluid-coupled natural frequencies sis also investigated.

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Design and Characteristics of AE Sensor for GIS by Finite Element Analys (유한요소해석을 이용한 GIS용 AE 센서의 설계와 특성)

  • Hong, Jae-Il;Lee, Byung-Hyo;Kim, Il-Nam;Cho, Tae-Kyung;Yoo, Ju-Hyun
    • Proceedings of the KIEE Conference
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    • 2000.07e
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    • pp.52-55
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    • 2000
  • In this paper, the coupled and the non-coupled vibration mode AE sensor for GIS were simulated by finite element analysis and manufactured, and characterized. The maximum sensitivity was 64.3 dB when the resonant frequency of the coupled vibration mode AE sensor was 166 kHz and the maximum sensitivity was 58.9 dB when the resonant frequency of the non-coupled mode AE sensor was 265 kHz. The coupled vibration mode AE sensor responded higher than the non-coupled vibration mode AE sensor at the partial discharge detection in GIS.

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Study on the Vibration Reduction Characteristics of Floating Floors Used in Railway Vehicles (철도차량에서 사용하는 부유상구조의 진동절연특성에 관한 연구)

  • Woo, Kwan-Je;Park, Hee-Jun
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.305-309
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    • 2006
  • In this paper vibration reduction characteristics of floating floors used in railway vehicles are studied. Vibration reduction characteristics are compared through a series of tests for elastically-coupled floor and rigidly-coupled floor. It was found that elastically-coupled floor has larger vibration reduction amount than rigidly-coupled floor. Around the fundamental natural frequency, however, elastic floor has poor vibration reduction effect than rigid floor. Measures to reduce structure-borne noise are also discussed based on the test results. Structure-borne noise for running railway vehicles cannot be reduced by an effort to deviate resonance between natural frequency of floors and major exciting forces. Instead, reducing vibration level of top floor and using covers which have low sound radiation coefficient will be effective for reducing structure-borne noise.

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Vibration Power Flow Analysis of Coupled Shell Structures (연성된 쉘 구조물의 진동 파워흐름해석)

  • Kim, Il-Hwan;Hong, Suk-Yoon;Park, Do-Hyun;Kil, Hyun-Gwon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.352.2-352
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    • 2002
  • In this paper, Power Flow Analysis (PFA) method has been applied to the prediction of vibration energy density and intensity of coupled shell structures in the medium-to-high frequency ranges. To consider the wave transformation at joint between shell elements, power transmission and reflection coefficients are investigated for various joint angles, and here Donnell-Mushtari thin shell theory has been used. (omitted)

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Experimental Analysis of Power Transmission and Reflection In a Coupled Plate (연성평판에서의 파워투과 및 반사 특성 실험 해석)

  • Lee, Y.H.;Kil, H.G.;Lee, H.H.;Lee, K.H.;Hong, S.Y.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11b
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    • pp.170-173
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    • 2005
  • The objective of this paper is to perform measurements of power transmission and reflection coefficients in a coupled plate. The coupled plate has been divided into 2 subsystems. The out-of-plane vibration has been only considered with assumption of relatively small in-plane vibration. The coupling loss factors have been measured with consideration of the power balance condition. The power transmission and reflection coefficients has been estimated from the measured values of the coupling loss factors. The measured power transmission and reflection coefficients have been compared with the corresponding theoretical coefficients in a semi-infinite coupled plate.

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Power Flow Analysis of Vibration of Coupled Plates Excited by a Point Force In an Arbitrary Direction (임의 방향 점가진력에 의한 연성 평판 진동의 파워흐름해석)

  • Kil, H.G.;Choi, J.S.;Hong, S.Y.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.301-308
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    • 2000
  • The power flow analysis(PFA) has been performed to analyze the vibration of coupled plates excited by a point force in an arbitrry direction. The energy governing equations for longitudinal, shear and flexural waves were solved to predict the vibrational energy density and intensity. The wave transmission approach was used to consider the mode conversion at the joints of the coupled plates. Numerical results for energy density and intensity on the coupled plates were presented. Comparison of the results by PFA with exact results showed that PFA can be an effective tool to predict the spatial variation of the vibrational energy and intensity on the coupled plates at high frequencies.

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Bridge-vehicle coupled vibration response and static test data based damage identification of highway bridges

  • Zhu, Jinsong;Yi, Qiang
    • Structural Engineering and Mechanics
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    • v.46 no.1
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    • pp.75-90
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    • 2013
  • In order to identify damage of highway bridges rapidly, a method for damage identification using dynamic response of bridge induced by moving vehicle and static test data is proposed. To locate damage of the structure, displacement energy damage index defined from the energy of the displacement response time history is adopted as the indicator. The displacement response time histories of bridge structure are obtained from simulation of vehicle-bridge coupled vibration analysis. The vehicle model is considered as a four-degree-of-freedom system, and the vibration equations of the vehicle model are deduced based on the D'Alembert principle. Finite element method is used to discretize bridge and finite element model is set up. According to the condition of displacement and force compatibility between vehicle and bridge, the vibration equations of the vehicle and bridge models are coupled. A Newmark-${\beta}$ algorithm based professional procedure VBAP is developed in MATLAB, and used to analyze the vehicle-bridge system coupled vibration. After damage is located by employing the displacement energy damage index, the damage extent is estimated through the least-square-method based model updating using static test data. At last, taking one simply supported bridge as an illustrative example, some damage scenarios are identified using the proposed damage identification methodology. The results indicate that the proposed method is efficient for damage localization and damage extent estimation.

Free Vibration Analysis of Two Circular Plates Coupled with Bounded Fluid (갇힌 유체로 연성된 두 원판의 고유진동 해석)

  • 정경훈;박근배;장문희;정명조
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.213-219
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    • 2001
  • This paper deals with the free vibration of two identical circular plates coupled with a bounded fluid. An analytical method based on the [mite Fourier-Bessel series expansion and Rayleigh-Ritz method is suggested. In the theory, it is assumed that the ideal fluid is filled in a rigid cylindrical container and the two plates are clamped along the plate edges. The proposed method is verified by the finite element analysis using commercial software with a good accuracy. Two transverse vibration modes, namely in-phase and out-of-phase, are observed alternately in the fluid-coupled system when the number of nodal circles increases for the fixed nodal diameter. The effect of gap between the plates on the fluid-coupled natural frequency is also investigated.

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Vibration Analysis of Two Unequal Circular Plates Coupled with a Fluid (유체로 연성되고 크기가 다른 두 원판의 진동해석)

  • 정경훈;최순
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.258-262
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    • 2004
  • An analytical method for the free vibration of two circular plates coupled with a fluid was developed by the Rayleigh-Ritz method. The two plates with unequal thickness and diameter are clamped along the cylindrical vessel wall. It is assumed that the fluid bounded by a rigid cylindrical vessel is incompressible and non-viscous. The wet mode shape of the circular plates is assumed as a combination of the dry mode shapes of the plates. The fluid motion is described by using the fluid displacement potential and determined by using the compatibility conditions along the fluid interface with the plate. Minimizing the Rayleigh quotient based on the energy conservation gives a eigenvalue problem. It is found that the theoretical results can predict well the fluid-coupled natural frequencies with excellent accuracy comparing with the finite element analysis result.

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