• Title/Summary/Keyword: 평면내 자유진동

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Free In-plane Vibration of a Clamped Circular Plate (고정된 원형 플레이트의 평면내 자유진동)

  • Park, Chan-Il
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.836-839
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    • 2005
  • The in-plane vibration response of a clamped circular plate should be predicted in many applications. Up to now, papers on the in-plane vibration of rectangular plate are published. However, analytical derivation on the in-plane vibration of the clamped circular plate is not carried out. Therefore, the in-plane vibration of the clamped circular plate is the concern of this paper. In order to derive the equations of motion for the clamped circular plate in the cylindrical coordinate, the kinetic energy and potential energy for the in-plane behavior are obtained by us ing the stress-strain-displacement expressions. Application of Hamilton's principle leads to two sets of differential equations. These displacement equations were highly coupled. It is possible to obtain a simpler set of equations by introducing Helmholtz decomposition. Substituting them into the coupled differential equations, we obtain the uncoupled equations of motion. In order to solve them, we assume that the solutions are harmonic. Then, they lead to the wave equations. Using the separation of variable, we obtain the general solutions for the equations. Based on the solutions, the displacements for r and $\theta$ direction are assumed. Finally we obtain the frequency equation for the clamped circular plate by the application of boundary conditions. The derived equation is compared with the finite element analysis for validation by using the some numerical examples.

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Vibration Analysis of Curved Beams Using Differential Quadrature (수치해석(미분구적법 DQM)을 이용한 곡선보의 진동분석)

  • Ki-Jun Kang
    • Journal of the Korean Society of Safety
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    • v.14 no.1
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    • pp.199-207
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    • 1999
  • The differential quadrature method (DQM) is applied to computation of eigenvalues of the equations of motion governing the free in-plane and out-of-plane vibrations for circular curved beams. Fundamental frequencies are calculated for the members with various end conditions and opening angles. The results are compared with existing exact solutions and numerical solutions by other methods (Rayleigh-Ritz, Galerkin or FEM) for cases in which they are available. The differential quadrature method gives good accuracy even when only a limited number of grid points is used.

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In-Plane Vibration Analysis of Curved Beams Considering Shear Deformation Using DQM (전단변형이론 및 미분구적법을 이용한 곡선보의 내평면 진동해석)

  • Kang, Ki-Jun;Kim, Byeong-Sam
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.5
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    • pp.793-800
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    • 2006
  • DQM(differential quadrature method) is applied to computation of eigenvalues of the equations of motion governing the free in-plane vibration fur circular curved beams including both rotatory inertia and shear deformation. Fundamental frequencies are calculated for the members with clamped-clamped end conditions and various opening angles. The results are compared with numerical solutions by other methods for cases in which they are available. The differential quadrature method gives good accuracy even when only a limited number of grid points is used.

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Free-vibration Characteristics of Two-I-girder Steel Bridges Curved in Plan (소수주형 수평곡선 강교량 상부구조의 자유진동 특성 분석)

  • Lee, Kee Sei;Kim, Seungjun
    • Journal of Korean Society of Steel Construction
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    • v.28 no.5
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    • pp.365-371
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    • 2016
  • In the case of the superstructure which is consist of two I girders and slab, the section can behave as II section, so that the neutral axis with respect to out of plane direction flexure can be regarded as major axis. Therefore in-plane flexural mode might govern the free vibration mode. Meanwhile, horizontally curved girders always experience not only bending moments but also torsional moments although the primary load is usually supposed to be gravitational load. The interaction due to bending and torsional moments make the behavior complicated and torsional mode may govern the free vibration mode. In other words, structure can have different dynamic characteristic due to its initial curvature. In this research, using 3-dimensional sell elements, free-vibration analyses are carried out due to initial curvature. The analysis models are assumed to be composite and non-composite and finally natural frequency and eigen mode are discussed.

In-Plane Extensional Vibration Analysis of Curved Beams using DQM (미분구적법을 이용한 곡선보의 태평면 진동분석)

  • Kang, Ki-Jun;Kim, Byeong-Sam
    • Journal of the Korean Society of Safety
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    • v.17 no.1
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    • pp.99-104
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    • 2002
  • DQM(differential quadrature method) is applied to computation of eigenvalues of the equations of motion governing the free in-plane vibration for circular curved beams including mid-surface extension and the effects of rotatory inertia. Fundamental frequencies are calculated for the members with various end conditions and opening angles. The results are compared with numerical solutions by other methods for cases in which they are available. The differential quadrature method gives good accuracy even when only a limited number of grid points is used.

A Stusy on the Coupled Vibration of Train Wheel and Pail - Dynamic Characteristics of Train Wheel with the Stepped Thickness - (車輪과 鐵路의 連成振動에 관한 硏究)

  • 김광식;박민태
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.1
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    • pp.63-73
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    • 1987
  • This study is a part of the research on the coupled vibration of train wheel with the stepped thickness and rail. The research was conducted for the purpose of examining the dynamic characteristics of train wheel at the running state and preventing the vibrations of the high speed railway. The stress at the boundary surface of web and rim, .sigma.$_{c}$, was analyzed in consideration of the uniform In-plane compressive stress depending on the conditions of rolling and the In-plane compressive stress depending on the rotation of train wheel. Then the equation of transverse vibration of the annular plate with the stepped thickness was analyzed by Rayleigh-Ritz's method. As a result of study, it was known that the rotational speed increase the natural frequency slightly and the acceleration level highly while the reaction force between train wheel and rail decrease the natural frequency linearly and the critical buckling is generated at n=1.

In-Plane Vibration Analysis of Asymmetric Curved Beams Using DQM (DQM을 이용한 비대칭 곡선보의 내평면 진동해석)

  • Kang, Ki-Jun;Kim, Young-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.8
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    • pp.2734-2740
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    • 2010
  • The free in-plane vibration of asymmetric circular curved beams with varying cross-section is analyzed by the differential quadrature method (DQM) neglecting transverse shearing deformation. Natural frequencies are calculated for the beams with various opening angles and boundary conditions. Results obtained by the DQM are compared with available results by other methods in the literature. It is found that the DQM gives the good accuracy even with a small number of grid points.

A Study on the Natural Frequency of Al Square Plates with a Brass Inclusion using Rule of Mixtures (혼합법칙을 이용한 황동 개재물이 있는 Al 정사각판의 고유진동수 해석)

  • Lee, Youn-Bok;Lee, Se-Hoon;Lee, Young-Shin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.19 no.4 s.74
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    • pp.399-406
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    • 2006
  • The natural frequencies of Al square plates with a brass inclusion were analyzed by the rule of mixtures. The rule of mixtures is the method to derive natural frequency mutiplying effective inplane wane speed and nondimensional frequency parameters. Numerical models were Al square plates with an inclusion with cantilever type, 2 clamped edge-2 free edge type, 3 clamped edge-1 free edge type and fully clamped edge type. In cantilever type plates, 2 clamped edge-2 free edge type plates and 3 clamped edge-1 free edge plates with an inclusion, good agreement within 10% obtained from rule of mixtures' results and numerical analysis results within inclusion area ratio 1/9. It was found that the natural frequencies of the cantilever type, 2 clamped edge-2 free edge type and 3 clamped edge-1 free edge type plates with an inclusion decrease as the size of inclusion increases when inclusion is located center of plates. And when the density of inclusion is less than the plates, natural frequency of plates with an inclusion increases as the size of inclusion increases.