• Magazine of the Korea Concrete Institute
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• v.3 no.2
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• pp.133-145
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• 1991

The essential difference between precast concrete structures and in situ concrete structures lies in the precast concrete panel structres, it is necessary to understand the bahavior of joints and their implications regarding overall structural behavior. Form such a point of view, this experimental study observes the components and joint behavior under the stress states expected of precast concrete panel structures subjected to lateral loads. 2 full-scale subassemblages were fabricated and tested. The test results show that the characteristics of horizontsl joints and wall coupling beams mainly govern the whole hahavior of P.C. structres.

• Structural Engineering and Mechanics
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• v.62 no.5
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• pp.519-535
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• 2017

In this article, static analysis of a magneto-electro-elastic (MEE) beam subjected to various thermal loading and boundary conditions has been investigated. Influence of pyroeffects (pyroelectric and pyromagnetic) on the direct quantities (displacements and the potentials) of the MEE beam under different boundary conditions is studied. The finite element (FE) formulation of the MEE beam is developed using the total potential energy principle and the constitutive equations of the MEE material taking into account the coupling between elastic, electric, magnetic and thermal properties. Using the Maxwell electrostatic and electromagnetic relations, variation of stresses, displacements, electric and magnetic potentials along the length of the MEE beam are investigated. Effect of volume fractions, aspect ratio and boundary conditions on the direct quantities in thermal environment has been determined. The present investigation may be useful in design and analysis of magnetoelectroelastic smart structures and sensor applications.

• Structural Engineering and Mechanics
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• v.10 no.1
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• pp.81-92
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• 2000

This study is an investigation of the effect of cracks on the dynamical characteristics of a cantilever beam, having multiple open-edge transverse cracks. The flexibilities due to crack have been identified for several crack depths and locations. In the study the finite element method and component mode synthesis methods are used. Coupling the components is performed by a flexibility matrix taking into account the interaction forces. Each component is modelled by cantilever beam finite elements with two nodes and three degrees of freedom at each node. The results obtained lead to conclusion that, by using the drop in the natural frequencies and the change in the mode shapes, the presence and nature of cracks in a structure can be detected. There is some counter-evidence, however, that the effects due to multiple cracks may interact to make detection more difficult than for isolated cracks.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.399-406
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• 2001

Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural bending-torsion coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1216-1221
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• 2000

Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, 'rotary inertia' and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.4
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• pp.374-383
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• 2011

A numerical model based on a mode method coupling beams and a rectangular plate is proposed to estimate radiation characteristics of an edge-clamped rectangular plate. The radiation efficiency and radiation power in the audio frequency range including the critical frequency can be predicted. The proposed model is rather simple and straightforward and gives reliable results comparing to the previous studies. The estimated radiation characteristics are compared to those of the pinned condition plates and also to those based on the formulae proposed by Maidanik. The radiation efficiency of the clamped plate seems a little higher than that of the pinned plate in the frequency range of corner and edge modes. It is explicitly shown that the power as well as efficiency at high frequencies is not influenced by these edge boundary conditions.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.8
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• pp.742-751
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• 2013

The vibration analysis of a rotating cantilever beam made-up of functionally graded materials is presented based on Timoshenko beam theory. The material properties of the beams are assumed to be varied through the thickness direction following a simple power-law form. The frequency equations, which are coupled through gyroscopic coupling terms, are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. In this study, resulting system of ordinary differential equations shows the effects of power-law exponent, angular speed, length to height ratio and Young's modulus ratio. It is believed that the results will be a reference with which other researchers and commercial FE analysis program, ANSYS can compare their results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.303-310
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• 2002

The bending vibration and thermal flutter instability of spacecraft booms modeled as circular thin-walled beams of closed cross-section and subjected to thermal radiation loading is investigated in this paper. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferantially uniform system(CUS) configuration are exploited in connection with the structural flapwise bending-lagwise bending coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. The numerical simulations display deflection time-history as a function of the ply-angle of fibers of the composite materials, damping factor, incident angle of solar heat flux, as well as the boundary of the thermal flutter instability domain. The adaptive control are provided by a system of piezoelectric devices whose sensing and actuating functions are combined and that an bonded or embedded into the host structure.

• Journal of the Optical Society of Korea
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• v.15 no.2
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• pp.187-195
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• 2011

We have designed two photonic crystal waveguide (PCW) structures with output focused beams in order to achieve more coupling between photonic devices and decrease the mismatch losses in photonic integrated circuits. PCW with coupled resonator optical waveguide (CROW) termination has been optimized by both one dimensional (1D) and seven dimensional (7D) particle swarm optimization (PSO) algorithms by evaluating the fitness function by the finite difference time domain (FDTD) method. The 1D and 7D-optimizations caused the factors of 2.79 and 3.875 improvements in intensity of the main lobe compared to the non-optimized structure, whereas the FWHM in 7D-optimized structure was increased, unlike the 1D case. It has also been shown that the increment of focusing causes decrement of the bandwidth.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.295-298
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• 2005

Coupled shear wall(CSW) has been adopted as a lateral force resisting system in building frame structures. New Zealand code recommends the capacity design in designing the CSW. Capacity design based on using moment redistribution of member force may provide the economical benefit to designer. In this study, CSW's are designed by both capacity design and strength -based design. The design results and the seismic performance are compared by using nonlinear static analyses. The amount of reinforcement of shear wall and the section area of steel coupling beams by capacity design appear to be reduced by 19$\%$ and 17$\%$, respectively. Also CSW designed by capacity design shows good seismic performance at the ultimate state.