• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.782-787
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• 1995

Rubber isolator has many advantages compared with steel spring mount. Rubber has high internal damping and can be formed various shape depending on specific purpose. On the contrary, low modulus of elasticity of rubber results the instability of rubber isolator by buckling phenomenon. This paper presents the development of shear type rubber isolator for industrial application by using shear rigidity property of rubber. The static load-deflection characteristics of developed isolator has been analyzed by the FEM. Consequently, the static load testing and a measure of the effectiveness of a vibration isolator in terms of force transissibility for developed isolator have been carried out.

• Structural Engineering and Mechanics
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• v.64 no.6
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• pp.751-763
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• 2017

This article deals with the buckling behaviour of multilayered magneto-electro-elastic (MEE) plate subjected to uniaxial and biaxial compressive (in-plane) loads. The constitutive equations of MEE material are used to derive a finite element (FE) formulation involving the coupling between electric, magnetic and elastic fields. The displacement field corresponding to first order shear deformation theory (FSDT) has been employed. The in-plane stress distribution within the MEE plate existing due to the enacted force is considered to be equivalent to the applied in-plane compressive load in the pre-buckling range. The same stress distribution is used to derive the potential energy functional. The non-dimensional critical buckling load is accomplished from the solution of allied linear eigenvalue problem. Influence of stacking sequence, span to thickness ratio, aspect ratio, load factor and boundary condition on critical buckling load and their corresponding mode shape is investigated. In addition, static deflection of MEE plate under the sinusoidal and the uniformly distributed load has been studied for different stacking sequences and boundary conditions.

• Structural Engineering and Mechanics
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• v.10 no.3
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• pp.197-209
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• 2000

The effects of weight and axial inertia of a beam are taken into account for studying the nonlinear vibration of the Timoshenko beam due to external loads. The combination of Galerkins method and Runge-Kutta method are employed to obtain the dynamic responses of the beam. A concentrated force and a two-axle vehicle traversing on the beam are taken as two examples to investigate the response characteristics of the beam. Results show that the effect of axial inertia of the beam increases the fundamental period of the beam. Further, both the dynamic deflection and the dynamic moment of the beam obtained with including the effect of axial inertia of the beam are greater than those of the beam without including that effect of the beam.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.178.4-178
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• 2001

In this paper a self-tuning gain-scheduled skyhook control for semi-active suspension systems is investigated. The dynamic characteristics of a continuously variable damper including electro-hydraulic pressure control valves is analyzed. A 2-d.o.f. time-varying quarter-car model that permits variations in sprung mass and suspension spring coefficient is considered. The self-tuning skyhook control algorithm proposed in this paper requires only the measurement of body acceleration. The absolute velocity of the sprung mass and the relative velocity of the suspension deflection are estimated by using integral filters. The skyhook gains are gain-scheduled in such a way that the body acceleration and the dynamic tire force are optimized. An ECU prototype ...

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.922-929
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• 2006

In this study, flow characteristics of the FPN (Fountain Pen Nano-Lithography) using active membrane pumping are investigated. This FPN has integrated chamber, micro channel, and high capacity reservoir for continuous ink feed. The most important aspect in this probe provided control of fluid injection using active membrane pumping in chamber. The flow rates in channel by capillary force are theoretically analyzed, including the control of mass flow rates by deflection of membrane. The above results are compared with numerical simulations that calculated by commercial code, FLUENT. The velocity of fluid in micro channel shows linear behaviors. And the mass flows are proportional to the second order function of pumping pressure that is imposed to membrane.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.1-30
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• 2008

When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect; its state equation remains always valid, except, it is named in more by calorically imperfect gas. The aim of this work is to trace the profiles of the supersonic axisymmetric Minimum Length Nozzle to have a uniform and parallel flow at the exit section, when the stagnation temperature is taken into account, lower than the dissociation threshold of the molecules, and to have for each exit Mach number and stagnation temperature shape of nozzle. The method of characteristics is used with the algorithm of the second order finite differences method. The form of the nozzle has a point of deflection and an initial angle of expansion. The comparison is made with the calorically perfect gas. The application is for air.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.8
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• pp.487-494
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• 2000

This paper describes the design, fabrication and experiments of surface-micromachined aluminum micromirror array with hidden pin-joints. Instead of the conventional elastic spring components as connection between mirror plate and supporting structure, we used pin-joint composed of pin and staples to support the mirror plate. The placement of pin-joint under the mirror plate makes large active surface area possible. These flexureless micromirrors are driven by electrostatic force. As the mirror plate has discrete deflection angles, the device can be ap;lied to adaptive optics and digitally-operating optical applications. Four-level metal structural layers and semi-cured photoresist sacrificial layers were used in the fabrication process and sacrificial layers were removed by oxygen plasma ashing. Static characteristics of fabricated samples were measured and compared with modeling results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.846-851
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• 2004

Static and dynamic responses of micro cantilever beam structures undertaking electrostatic forces are obtained employing Galerkin's method based on Euler beam theory. Variations of static and dynamic responses as well as resonant frequencies are estimated for several sets of beam properties and applied voltages. It is shown that the applied voltage influences the deflection and the modal characteristics significantly. Such information can be usefully employed for the design of MEMS structures.

• KCI Concrete Journal
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• v.11 no.3
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• pp.99-107
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• 1999

In designing the Prestressed concrete box-girder bridge. dead load, prestressing force, creep and shrinkage of concrete are the main factors which influence the camber and deflection of segmental concrete structure under construction. Among these factors the creep and shrinkage are the functions of the time-dependent property which. therefore, must be considered with time. The prediction model for estimating creep and shrinkage of concrete has been suggested by ACI, CEB/FIP, JSCE and KSCE design code and EMM, AEMM, RCM, IDM and SSM has been suggested for analytical method in consideration of time-dependent characteristics. In this study the creep test was carried out for four different curing ages of concrete which were applied to the Prestressed concrete structure at the construction site, and the results of test were compared with the values of creep prediction proposed by the design code. Also the creep test was performed with step-wise incremental stresses and the results were compared to the analytical values.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.324-331
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• 2016

The present study focuses on the characteristics of a supersonic jet flowing from a rectangular nozzle exit on a flat plate. Flow visualization techniques using schlieren and kerosene-lampblack tracing are utilized to investigate shock reflection structures and boundary-layer separations over a flat plate. Wall pressure measurements are also carried out to quantitatively analyze the flow structures. All observations are repeated for multiple jet flow boundary conditions by varying the flap length and nozzle pressure ratio. The experimental results show that the jet flow structures over the flat plate are highly three-dimensional with strong bleeding flows from the plate sides, and that they are sensitive to plate length and nozzle pressure ratio. A multi-component force measurement device is also utilized to observe the characteristics of the jet flow thrust vectoring over the plate. The maximum thrust deflection angle of the jet is about $8^{\circ}$, demonstrating the applicability of thrust vector control via a flat plate installed at the nozzle exit.