• Journal of the Korea Concrete Institute
• /
• v.17 no.6 s.90
• /
• pp.1001-1009
• /
• 2005

The usefulness of walls in the structural planning of multistory buildings has long been recognized. When walls are situated in advantageous positions in a buildings, they can be very efficient in resisting lateral load. Specially coupled shear wall system is the primary lateral load resisting system of buildings. It is customary to refer to such walls as being 'coupled' by coupling beams. The coupling beams must exhibit excellent strength, stiffness ductility and energy dissipation capacity. To achieve these demands for steel coupling beam, steel coupling beam with Face Bearing Plate(FBP) embedded in the reinforced concrete walls is proposed. A comprehensive experimental test involving 2 steel coupling beam with and without FBP has been performed. Through experimental study, the evaluation of the advantage of that was establish and proposed the failure mode.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.10
• /
• pp.743-750
• /
• 2016

In this research, the effects of the strength and stiffness of shear walls on the design strength of coupling beams are studied in the shear wall-coupling beam structural system widely used as the lateral-drift resistant system of high-rise buildings. The results show that the design strength of the coupling beams decreases with decreasing concrete strength and core wall thickness, but the shape remains unchanged. In all six models, the design strength of the coupling beams has the largest value at the 10~15th floors in a 40-story building. In other words, the design strength of the coupling beams has the largest value at 0.25H~0.375H where the inflection point exists. The thicker the walls, the smaller the change in the member forces. The thickness of the coupled shear walls has more influence on the design strength of the coupling beams than the concrete strength.

• Transactions of Materials Processing
• /
• v.21 no.7
• /
• pp.441-446
• /
• 2012

A sequential coupled field analysis of electromagnetic free bulging was performed by using FEM. A 2D axi-symmetric electromagnetic model based on the magnetic vector potential is proposed for the calculation of magnetic field and Lorentz's forces. The Newmark integration method is used to calculate the transient dynamic plastic deformation of sheet during free bulging. In the finite element model, the effect of sheet deformation on the electromagnetic field analysis is taken into consideration. In order to confirm the sequential electromagnetic-mechanical coupling analysis, an experiment with an electromagnetic forming apparatus was conducted. The results showed that the final bulge height of the sheet predicted from the proposed method is in good agreement with experimentally measured height.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.551-556
• /
• 2004

The theoretical method is developed to investigate the vibration characteristics of the combined cylindrical shells with an annular plate joined to the shell at any arbitrary axial position. The structural rotational coupling between shell and plate is simulated using the rotational artificial spring. For the translational coupling, the continuity conditions for the displacements of shell and plate are used. For the uncoupled annular plate, the transverse motion is considered and the in-plane motions are not. And the additional transverse and in-plane motions of the coupled annular plate by shell deformation are considered in analysis. Theoretical formulations are based on Love's thin shell theory. The frequency equation of the combined shell with an annular plate is derived using the Rayleigh-Ritz approach. The effect of inner-to-outer radius ratio, axial position and thickness of annular plate on vibration characteristics of combined cylindrical shells is studied. To demonstrate the validity of present theoretical method, the finite element analysis is performed.

• Korean Journal of Optics and Photonics
• /
• v.13 no.3
• /
• pp.228-234
• /
• 2002

We report theoretical investigation on the polarization selective coupling characteristics of a side-polished fiber directional coupler with a thin metal interlayer. Based on normal mode theory the coupling properties of the device under various structural conditions are analyzed. It is shown that the coupling strength between TE modes weakens rapidly with increase or metal interlayer thickness, whereas that between TM modes becomes stronger. The design conditions of the polarization splitter using the coupler to achieve high extinction ratio and low insertion loss are presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1918-1924
• /
• 2000

Dynamic characteristics of a vertically coupled structure used for micro gyroscopes, is studied. The coupled motion between the reference and sensing vibrations causes the zero-point output which means non-zero sensing vibration without angular velocity. This structural coupling deteriorates sensing performance and dynamic stability. We theoretically analyze dynamic characteristics associated the coupling phenomenon. Effects of reference frequency and coupling factor on the rotational direction and amplitude of elliptic oscillation are studied. A method to predict the existence of curve veering or crossing in frequency trajectories is introduced for the application to the design of micro gyroscopes with a vertically decoupled structure.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.176.1-176.1
• /
• 2014

Graphene has attracted an increasing attention due to its extraordinary electronic, mechanical, and thermal properties. Especially, the two dimensional (2D) sheet of graphene with an extremely high surface to volume ratio has a great potential in the preparation of multifunctional nanomaterials, as 2D supports to host metal nanoparticles (NPs). Copper oxide is widely used in various areas as antifouling paint, p-type semiconductor, dry cell batteries, and catalysts. Although the copper oxide(II) has been well known for efficient catalyst in C-N cross-coupling reaction, copper oxide(I) has not been highlighted. In this research, CuO and Cu2O nanoparticles (NPs) dispersed on the surface of grapehene oxide (GO) have been synthesized by impregnation method and their morphological and electronic structures have been systemically investigated using TEM, XRD, and XAFS. We demonstrate that both CuO and Cu2O on graphene presents efficient catalytic performance toward C-N cross coupling reaction. The detailed structural difference between CuO and Cu2O NPs and their effect on catalytic performance are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.359-364
• /
• 2002

Statistical energy method is widely used for the prediction of vibrational and acoustical behavior of complex structures, such as ship building and automobile in mid-, high frequency ranges. However. in order to convince this SEA result, it is important to verify estimated SEA parameters, e. g. modal density, energy in each subsystem, damping loss factor, coupling loss factor. with possible other method. For modal density parameter, the experimental estimations via Experimental Modal Analysis are checked with those from finite element method for both beam- plate and plate-plate cans. Loss factors are calculated by Lyon's simple method for the two subsystem. finally. modal experiments are carried out by varying the mass added on the junction of two subsystem for the purpose of investigating the influence on the coupling loss factor's behavior.

• Journal of KSNVE
• /
• v.10 no.5
• /
• pp.880-885
• /
• 2000

In a verical type, vibratory gyroscope, the coupled motion between the reference and sensing vibrations causes the zero-point output which means non-zero sensing vibration without angular velocity. This structural coupling leaks to an inherent discrepancy between the natural frequencies of the reference and sensing oscillations, causing the degradation of the sensing performance and dynamic stability. In this paper, the dynamic characteristics associated the coupling phenomenon are theoretically analyzed. Effects of reference frequency and coupling factor on the rotational direction and amplitude of elliptic oscillation are studied. A technique to predict the existence of curve veering of crossing in frequency trajectories is introduced to apply the design of micro gyroscopes with decoupled structures.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.15 no.3
• /
• pp.824-833
• /
• 1991

본 연구에서는 차체구조계의 진동모드 변수와 차실음향계의 음향모드변수들이 어떻게 관련되어 차실소음을 결정하는 가를 밝혔다. 그 결과, 수치해석 결과의 효용 성을 높이고 실내소음 평가방법을 체계화 시킬 수 있었으며, 효과적인 소음저감을 위 한 유용한 자료를 얻을 수가 있었다. 한편, 이제까지의 차실소음의 응답해석에서 가 장 큰 오차의 발생요인은 차체의 구조진동 모드데이타인데, 본 연구에서는 유한요소해 석 대신 모드시험 결과를 이용함으써, 유한요소 모델리이 어려운 경우의 소음 해석의 신뢰도를 높일수가 있었다.