• Title/Summary/Keyword: galerkin principle

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Effect of Boundary Conditions on the Stability Characteristics of Nanopipes (경계조건에 따른 나노파이프의 안정성 특성)

  • Choi, Jong-Woon;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.10
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    • pp.1057-1064
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    • 2008
  • In this paper, static and oscillatory instability of nanopipes conveying fluid and modelled as a thin-walled beam is investigated. Effects of boundary conditions and non-classical transverse shear and rotary inertia are incorporated in this study. The governing equations and the three different boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Variations of critical flow velocity for different boundary conditions of carbon nanopipes are investigated and pertinent conclusion is outlined.

Flow-induced Vibration of Carbon Nanopipe with Nonlocal Effect (Nonlocal 효과를 고려한 탄소나노파이프의 유체유발 진동)

  • Choi, Jong-Woon;Kim, Sung-Kyun;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.1
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    • pp.38-45
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    • 2012
  • In this paper, flow-induced flutter instability of a cantilever carbon nanotube conveying fluid and modelled as a thin-walled beam is investigated. Analytically nonlocal effect, transverse shear and rotary inertia are incorporated in this study. The governing equations and the boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extended Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Variation of critical flow velocity of carbon nanopipes based on three different models such as analytically nonlocal model, partially nonlocal model, and local model are investigated and pertinent conclusion is outlined.

Vibration Analysis of Composite Cylindrical Shells Subjected to Electromagnetic and Thermal Fields (자기장 및 열하중을 받는 복합재료 원통셸의 진동해석)

  • Park, Sang-Yun;Kim, Sung-Kyun;Choi, Jong-Woon;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.8
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    • pp.791-799
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    • 2012
  • In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT was performed through discretization of equations of motion and boundary condition. Structural model of laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations(Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, and stacking sequence are investigated and pertinent conclusions are derived.

Stability Analysis of Nanopipes Considering Nonlocal Effect (Nonlocal 효과를 고려한 나노파이프의 안정성 해석)

  • Choi, Jongwoon;Song, Ohseop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.4
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    • pp.324-331
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    • 2013
  • In this paper, static and oscillatory instability of a nanotube conveying fluid and modeled as a thin-walled beam is investigated. Analytically nonlocal effect, effects of boundary conditions, transverse shear and rotary inertia are incorporated in this study. The governing equations and boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extended Galerkin method which enables us to obtain more accurate results compared with conventional Galerkin method. Variations of critical flow velocity of carbon nanopipes with two different boundary conditions based on the analytically nonlocal theory and partially nonlocal theory are investigated and pertinent conclusions are outlined.

Nonlinear Stability Characteristics of Carbon Nanotubes (탄소나노튜브의 비선형 안정성 해석)

  • Choi, Jong-Woon;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.7
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    • pp.699-709
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    • 2009
  • In this paper, the nonlinear dynamics and the stability of nanopipes conveying fluid and modelled as a thin-walled beam is investigated. Effects of boundary conditions, geometric nonlinearity, non-classical transverse shear and rotary inertia are incorporated in this study. The governing equations and the three different boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Variations of critical flow velocity for different boundary conditions of carbon nanopipes are investigated and compared with linear case.

Stability Analysis of Multi-wall Carbon Nanotubes Conveying Fluid (유체유동에 의한 다중벽 탄소나노튜브의 안정성 해석)

  • Song, Oh-Seop;Yun, Kyung-Jae
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.6
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    • pp.593-603
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    • 2010
  • In this paper, vibration and flow-induced flutter instability analysis of cantilever multi-wall carbon nanotubes conveying fluid and modelled as a thin-walled beam is investigated. Non-classical effects of transverse shear and rotary inertia and van der Waals forces between two walls are incorporated in this study. The governing equations and the associated boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Cantilevered carbon nanotubes are damped with decaying amplitude for flow velocity below a certain critical value, however, beyond this critical flow velocity, flutter instability may occur. Variations of critical flow velocity with both radius ratio and length of carbon nanotubes are investigated and pertinent conclusion is outlined.

Flow-induced Vibration of Carbon Nanotubes Conveying Fluid (탄소나노튜브의 유체유발 진동)

  • Song, Oh-Seop;Choi, Jong-Woon;Gil, Bo-Ramm
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.242-249
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    • 2008
  • In this paper, flow-induced flutter instability of cantilever carbon nanotubes conveying fluid and modelled as a thin-walled beam is investigated. Non-classical effects of transverse shear and rotary inertia are incorporated in this study. The governing equations and the associated boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Cantilevered carbon nanotubes are damped with decaying amplitude for flow velocity below a certain critical value, however, beyond this critical flow velocity, flutter instability may occur. Variations of critical flow velocity with both radius ratio and length of carbon nanotubes are investigated and pertinent conclusion is outlined.

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A Study on the Thermal Stress Analysis of Axi-Symmetric Hollow Cylinder (축대칭 중공실린더의 길이방향 온도분포하의 열탄성응력 해석에 관한 연구)

  • Lee, Sang-Jin;Cho, Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.10
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    • pp.3152-3159
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    • 1996
  • Previous works about the cylindrical shape elastic body which is under longitudinal temperature distribution mostly show the results of free expansion, therefore exact thermo-elastic analysis is needed. The object of this work is to analyze the thermo-elastic problem of the hollow cylinder when the cylinder is under longitudinal temperature distribution. In this paper, the analytical solution is found by using Galerkin vector, and it is compared by the results of FEM. For displacements of cylinder, analytical values are almost same as the results of FEM, but free expansion is not fit for analytical solution and the results of FEM. stresses from analytical solution and the results of FEM show good agreement also. but the results are different near the end boundary, since St. Venant principle is applied.

Flow-induced Vibration of Carbon Nanotubes Conveying Fluid (탄소나노튜브의 유체유발 진동)

  • Choi, Jong-Woon;Gil, Bo-Ramm;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.6
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    • pp.654-662
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    • 2008
  • In this paper, flow-induced flutter instability of cantilever carbon nanotubes conveying fluid and modelled as a thin-walled beam is investigated. Non-classical effects of transverse shear and rotary inertia are incorporated in this study. The governing equations and the associated boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Cantilevered carbon nanotubes are damped with decaying amplitude for flow velocity below a certain critical value, however, beyond this critical flow velocity, flutter instability may occur. Variations of critical flow velocity with both radius ratio and length of carbon nanotubes are investigated and pertinent conclusion is outlined.

Effect of Boundary Conditions on the Stability Characteristics of a Nanotube with Scale Effect (Scale Effect를 고려한 경계조건에 따른 나노튜브의 안정성 해석)

  • Choi, Jong-Woon;Yun, Kyung-Jae;Kim, Sung-Kyun;Park, Sang-Yun;Song, Oh-Seop
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.923-928
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    • 2012
  • In this paper, static and oscillatory instability of a nanotube conveying fluid and modelled as a thin-walled beam is investigated. Analytically nonlocal effect, effects of boundary conditions, transverse shear and rotary inertia are incorporated in this study. The governing equations and the two different boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Variations of critical flow velocity for different boundary conditions of a nanotube with analytically nonlocal effect, partially nonlocal effect and local effect of a nanotube are investigated and pertinent conclusion is outlined.

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