1990 Fiscal Year Final Research Report Summary
Analysis and Experiment on Dynamic Stability of Steel Structures Subjected to Dynamic In-Plane Force
| Project/Area Number |
01550368
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
土木構造
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| Research Institution | Nagasaki University |
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Principal Investigator |
TAKAHASHI Kazuo Nagasaki University Faculty of Engineering Associate Professor, 工学部, 助教授 (30039680)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUDA Hiroshi Nagasaki University Faculty of Engineering Lecturer, 工学部, 講師 (20157324)
OKABAYASHI Takatoshi Nagasaki University Faculty of Engineering Associate Professor, 工学部, 助教授 (90039686)
TSUIJI Tsuneo Nagasaki University Faculty of Engineering Professor, 工学部, 教授 (40039673)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Bridge Vibration / Vibration of Structure / Parametric Vibration / Dynamic Stability / Dynamics of Structures / Cable |
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| Research Abstract |
Dynamic stability of steel structures such as cables and bridges subjected to in-plane dynamic load is analyzed by using analytical and experimental approaches. The results are as follows.
(1) Dynamic stability of a flat sag cable subjected to an axial periodic force is investigated. The investigated. The equation of motion of the cable is solved by the Galerkin method. Unstable regions are presented first for various sag-to-span ratios and ratios of wave speeds. Amplitudes of unstable motions are obtained using the nonlinear cable theory.
(2) Anti-symmetric response of a cable through bifurcation under in-plane symmetric time-varying load is analyzed. The in-plane nonlinear equations of motion of a cable under symmetric forcing are solved by a Galerkin method. The frequency range where the anti-symmetric responses occur is shown at first. Then, nonlinear symmetric response and the corresponding anti-symmetric response within the unstable region calculated by using the Runge-Kutta-Gill m
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ethod. Nonlinear coupling between symmetric and and anti-symmetric responses are observed in the particular sag-to-span ratios. Anti-symmetric responses in the present problem.
(3) Dynamic unstable regions and amplitudes of the responses of a beam subjected to a sinusoidally time-varying axial force for various boundary conditions and loading conditions are examined. Conservative and follower forces are considered for the fixed-free beam. Dynamic unstable regions which are obtained by the small deflection theory are discussed at first and amplitudes of unstable motions are obtained by the nonlinear theory of beams caused by axial force due to deflection and nonlinear curvature of beams.
(4) Dynamic stability problem of an annular sector plate subjected to in-plane dynamic moments at the radial edges is examined. The basic equation is reduced to a set of ordinary differential equations by applying a Galerkin method, and transformed into an eigen-value problem by using the harmonic balance method. The stability of the system can be directly determined from the sign of the real parts of the eigen-values.
(5) The nonlinear dynamic instability of an annular sector plate subjected to equal and opposite time-varying moments is examined. The equation of motion describing a large deflection of the annular sector plate based upon Berger's approximate equation is analyzed by the Galerkin method. The resulting equations for time variables are integrated by using the Runge-Kutta-Gill method. Numerical results are presented for various boundary conditions, damping forces, and static moments.
(6) Experimental results for anti-symmetric responses of the fixed-fixed beam subjected to symmetric forcing are presented and compared with theoretical results. Vertical and lateral vibrations of steel bridges under moving load are measured and discussed. Less
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Research Products
(16 results)
