• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.12 no.3
• /
• pp.109-115
• /
• 2000

Numerical model is proposed to estimate dynamic responses of riser with vortex excitation by inline current. Galerkin's finite decomposition method is implemented for the development of a numerical model and vortex excitation is modeled by coupled wake oscillator proposed by Blevins. The numerical results are inspected through the physical interpretation to give the verification and usefulness of the suggested numerical model.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.8
• /
• pp.2734-2740
• /
• 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.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.10 s.103
• /
• pp.1186-1194
• /
• 2005

In this paper, we have systematically formulated the equations concerned to the in-plane and out-of-plane motions and deformations of a thick circular beam by using the kinetic and strain energies in order to analyse natural frequencies of a thick ring. The effects of variation of radius of curvature across the cross-section and also the effects of bending shear, extension and twist are considered. The equations of motion for natural vibration analysis of a ring are obtained utilizing the cyclic symmetry of vibration modes of the ring. The frequencies calculated using thick ring model and thin ring model are compared and discussed with the ones obtained from finite element analysis using the method of cyclic symmetry with 20-node hexahedral solid elements for rings with the different ratio of radial thickness to mean radius.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.952-956
• /
• 2004

The soil-structure interactions are caused by the point sources of explosions, deriving piles, compaction of foundations and excavations those are frequently arose in the construction sites. Thus the analysis of soil-structure interactions is one of the most important subjects in the fields of dynamic analysis and vibration control. From this viewpoint, the aim of this study is to collect the basic data for designing foundation structures throughout understanding the dynamic structural behavior, which is embodied by the dynamic analysis of soil-structure systems. In this study, the dynamic analyses of stiffened thick plates subjected to in-plane stress on elastic foundations are carried out. The foundation is modeled as Pasternak foundation that includes the continuity effect of foundations. Also both the Mindlin plate theory and Timoshenko beam-column theory are used for analyzing the thick plates and beams, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.1185-1188
• /
• 2002

The objective of this paper is to apply experimental methods to measure the in-plane vibration intensity of a semi-infinite beam. Two experimental methods have been implemented to measure the in-plane vibration intensity of the beam. The first method is the cross spectral intensity measurement method using two accelerometers. The second method is the frequency response method using the only one acrelerometer. It has the advantages of shortening measurement time and reducing accelerometer phase error. Experimental results showed that those experimental methods can be effectively used to measure the structural In-plane vibration intensity.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.11
• /
• pp.864-872
• /
• 2002

In this study, the effect of planform curvature on the stability of coupled flow/structure vibration is examined in transonic and supersonic flow regions. The aeroelastic analysis for the frequency and time domain is performed to obtain the flutter solution. The doublet lattice method(DLM) in subsonic flow is used to calculate unsteady aerodynamics in the frequency domain. For all speed range, the time domain nonlinear unsteady transonic small disturbance code has been incorporated into the coupled-time integration aeroelastic analysis (CTIA). Two curved wings with experimental data have been considered in this paper MSC/NASTRAN is used for natural free vibration analyses of wing models. Predicted flutter dynamic pressures and frequencies are compared with experimental data in subsonic and transonic flow regions.

• Journal of KSNVE
• /
• v.2 no.4
• /
• pp.305-315
• /
• 1992

In order to investigate the effects of layer-wise in-plane displacements on vibration and damping characteristics of composite laminated plates, the finite element method based on the generalized laminated plate theory(GLPT) has been formulated. Specific damping capacity of each mode was obtained by modal strain energy method. To see the effect of transverse shear on deformation, the strain energy of stress components was computed. The accuracy of this study was examined for the cylindrical bending vibration of cross-ply plate strip. The results were very accurate compared with 3-D solutions. The numerical results show that through-thickness variation of in-plane displacements has not so much influence on the natural frequency, but has a great influence on the damping of composite plates, especially on the damping of thick composite plates since the damping is affected by local behavior while the natural frequency is affected by global behavior.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.728-731
• /
• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1994.10a
• /
• pp.521-528
• /
• 1994

레이저광의 우수한 가간섭성으로 인해서 거친표면으로 부터 확산된 광에서도 간섭현상을 볼 수가 있다, 이와 같은 레이져광의 독특한 특성으로 인해 나타나는 스페클은 광학적인 간섭계를 사용하여 광을 확산적으로 반사시키는 물체의 변형과 변위, 진동 등을 비접촉적으로 측정 할수 있게 되었다.이와같은 측정법으로써 Holography 간섭법, Speckle 간섭법, Speckle 사집법등이 있으며 비록 이러한 측정법들이 독립적으로 발전되었다 할지라도 기본적인 광학적인 배치와 함수들에 있어서는 유사한 특징을 가지고 있다. 따라서 본 연구에서는 주로 면내변형을 측정하기위한 스페클간섭법에 있어서의 스페클 사이즈와 그에 따른 측정 한계를 확인할 것이다.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1083-1087
• /
• 2009

We present an 1-dimensional annular disk element with which natural vibration of a circular plate can be analyzed accurately and facilely. The natural vibration characteristics of a circular plate with free outer boundary are analyzed by using the presented I-dimensional element. Its results are compared with the results obtained by utilizing 2-dimensional 8-node quadrilateral plane element and cyclic symmetry of the circular plate. And also, by comparing with the theoretical results of previous researchers, the accuracy and facility of the presented I-dimensional element are verified.