• 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.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.1
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• pp.95-106
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• 2001

When the crankshaft of diesel engine has more than 3 throws, which are arranged in a different plane, its vibration induces coupled motions, especially the coupled torsional and axial vibration. Nowadays, the torsional vibration which is influenced rather weak than axial one, can be theoretically calculated fairly accurately, but theoretical calculation results of the axial vibration which is influenced strongly from torsional vibration is not so good. To get accurate calculation results of axial vibration, coupled axial-torsional vibration must be treated. In this investigation, coupled effects of vibration of diesel engine propulsion shafting are analyzed theoretically and some simple calculation methods are also studied. On this first report, effects of coupling on natural frequencies and their modes are mainly studied, setting the each mass in 4 degrees of freedom.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.60-71
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• 2000

When the crankshaft of Diesel engine has more than 3 throws which are arranged in a different plane its vibration induces coupled motions especially the coupled torsional and axial vibration. Nowadays the torsional vibration which is influenced rather weak than axial one can be theoretically calculated fairly accurately but theoretical calculation results of the axial vibration which is influenced strongly from torsional vibration is not so good. To get accurate calculation results of axial vibration coupled axial-torsional vibration must be treated. in this investigation coupled effects of vibration of Diesel engine propulsion shafting are analyzed theoretically and some more simple calculation methods are also studied. On this first report effects of coupling on natural frequencies and their modes are mainly studied setting the each mass in 4 degrees of freedom. later this problem may be studied again by setting each mass as 6 degrees of freedom.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.468-473
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• 2004

The objective of this paper is to analyze the characteristics of wave transmission through various junctions in coupled beams. The in-plane vibration as veil as the out-of-plane vibration are generated due to the wave conversion at the junctions in the coupled beams. The out-of-plane vibration is associated with propagation of out-of-plane waves (flexural waves). The in-plane vibration is associated with propagation of in-plane waves (longitudinal and torsional waves). In order to effectively reduce vibration and structure-borne noise, it is necessary to understand the characteristics of wave conversion at various junctions in the coupled structures. The numerical results in this paper have showed the characteristics of wave transmission through various junctions in coupled beams. Those could be helpful to designer to develop the idea to reduce vibration and structure-borne noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.901-904
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• 2007

The power flow analysis (PFA) can be effectively used to predict structural vibration in medium-to-high frequency ranges. In this paper, vibration experiments have been performed to observe the analytical characteristics of the power flow analysis of the vibration of various coupled plates. Those plates include two plates coupled with angles of $90^{\circ}$\;and\;30^{\circ}$, respectively. In the experiment, the loss factor and the input mobility at a source point on each coupled plate have been measured. The data for the loss factors have been used as the input data to predict the vibration of the coupled plates with PFA. The frequency response functions have been measured over the surface of the coupled plates. The comparison between the experimental results and the predicted PFA results for the frequency response functions has been performed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.135-141
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• 1996

Numerical analysis techniques have been applied to obtain the vibroacoustic characteristics of the simplified model of a passenger-car cabin. Two kinds of coupled vibration-acoustic analysis, such as one-way coupling and full coupling, have been carried out via the interface between the results of vibration analysis by FEM and acoustic analysis by BEM. The comparison of two coupled analysis results show the fluid-structure interaction in terms of the coupled effect of the vibration and noise.

• International Journal of Ocean System Engineering
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• v.1 no.2
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• pp.76-88
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• 2011

The present study deals with the hydroelastic vibration analysis of structures in contact with fluid via coupled fluid-structure interaction (FSI) embedded with a finite element method (FEM) such that a structure displacement formulation is coupled with a fluid pressure-displacement formulation. For the preliminary study and validation of FEM based coupled FSI analysis, hydroelastic vibration characteristics of a rectangular plate in contact with fluid are first compared with the elastic vibration in terms of boundary condition and mode frequency. Numerical results from coupled FSI analysis have been shown to be rational and accurate, compared to energy method based theoretical solutions and experimental results. The effect of free surface on the vibration mode is numerically studied by changing the submerged depth of a rectangular plate. As a practical application, the hull structural vibration of 4,000 twenty-foot equivalent units (TEU) container ship is considered. Hydroelastic results of the ship hull structure are compared with those obtained from the elastic condition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.220-225
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• 2001

Asymmetric beams cause complicated vibration phenomena due to the inherent bending-torsion coupled vibration. In this paper, an exact dynamic element matrix for the bending-torsion coupled vibration of asymmetric beam is derived. An application of the derived exact dynamic element matrix is demonstrated by an illustrative example, wherein the natural frequencies by the proposed modeling method are compared with those available in the literature. Another numerical example is also illustrated which deals with a general beam with joints. The numerical study shows that the exact dynamic element model is useful for the dynamic analysis of asymmetric bending-torsion coupled beams.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.722-728
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• 2001

Applying a general coupled lateral and torsional vibration finite element model of gear pair element this paper intends to look into in detail the coupled lateral and torsional vibration characteristics in a turbo-chiller rotor bearing system, having a bull-pinion speed increasing gear. Investigations have been carried out systematically by comparing the uncoupled and coupled analyses natural vibration frequencies and their mode shapes upon varying the gear mesh stiffness, and also by comparing the strain energies of lateral and torsional vibration modes. Results have shown that some modes may have coupled lateral and torsional mode characteristics as the gear mesh stiffness increases over a certain value, and moreover that their associated dominant modes may be different from their initial modes, i.e., the dominant mode changes from an initial torsional one to a lateral one or from an initial lateral one to a torsional one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.352-357
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• 1997

The coupled vibration of a wheel-railway track system has been considered as that of a moving mass on a beam. In this paper, an analytical model is proposed to analyze the coupled vibration when a wheel travels on a railway track. The railway track supported by sleepers is considered as a beam on Winkler's foundations, and the wheel traveling on railway track at constant speed is considered as a moving mass. Hertz's contact stiffness is assumed between the wheel and railway track. Numerical results are compared with experimental ones to verify the validity of the numerical method. The numerical method in found to be efficient to analyze this system. Based on the numerical simulation, the appropriate analysis range of the beam model and the characteristics of coupled vibration are discussed.