• 한국지진공학회논문집
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• 제5권5호
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• pp.25-33
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• 2001

현재 국내에서 개발중인 액체금속로 원자로구조물의 내진설계 및 지진해석을 위하여 원자로내부에 존재하는 유체-구조물 상호작용을 고려한 단순지진해석 모델링 개발이 필수적이다. 이를 위하여 본 논문에서는 유체속에 잠긴 동축원통 구조물의 유체부가질량에 대한 이론적 배경을 검토하였으며 기존의 유체부가질량법을 고려하여 시간이력 지진응답해석을 수행할 수 있는 Runge-Kutta 수치해석 알고리즘을 사용한 해석코드를 개발하였다. 개발된 지진해석코드를 사용하여 유체속에 잠긴 두개의 동축원통 구조물의 진동특성과 지진응답에 대한 유체부가질량의 영향을 살펴보았다. 적용예로서 두개의 동축원통에 대한 단순지진해석모델을 가정하고 유체부가질량을 고려한 진동특성해석과 지진응답해석을 수행한 결과 유체가 채워진 동축원통 구조물은 유체와의 상호작용으로 인하여 구조물의 진동특성과 지진응답특성이 크게 영향을 받으며 지진응답해석시 연계항을 포함한 유체부가질량의 영향을 신중하게 고려할 필요가 있는 것으로 나타났다.

• 한국CDE학회논문집
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• 제8권1호
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• pp.19-26
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• 2003

This paper presents the structural analysis of RIROB(Reactor Inspection Robot). Actually, several analyses such as kinetodynamics analysis, fluid mechanics analysis and structural mechanics analysis etc. should be carried out in the design of RIROB. These analyses are executed through the use of com-puter aided engineering(CAE) systems. The kinetodynamics analysis is carried out using a simple fluid dynamic analysis model for the water flow over the sensor support surface instead of difficult fluid mechanics analysis. Simultaneously the structural mechanics analysis is carried out to obtain the mini-mum thickness of the RIROB housing. The minimum thickness of the RIROB housing is evaluated to be 1.0 ㎝ for the safe design of RIROB. The kinetodynamics analysis of RIROB is performed using ADAMS and the static structural mechanics analysis of RIROB is performed using NISA.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.465-470
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• 2001

In this study, the seismic analysis of rack structure with fluid-structure interaction is performed through use of the Finite Element Method(FEM) code ANSYS. Fluid-structure interaction can specify in terms of an hydrodynamic effect which is defined as the added mass per unit length divided by the area of the cross section. Using the Floor Response Spectrum(FRS) obtained through the time-history analysis, modal analysis and seismic analysis under Operating Basis Earthquake(OBE) and Safe Shutdown Earthquake(SSE) condition is carried out. The fluid-structure interaction effects on the rack structure are investigated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.661-665
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• 2000

A method of considering the fluid induced external force in structural dynamic analysis is presented in this study. The fluid induced pressure distribution around a structure in discrete number of orientation. and velocity is calculated by using a CFD code and tabulated as resultant forces and moments in a database. These forces and moments are interpolated and employed as external forces during the dynamic analysis of structure. The reliability and usefulness of the present method is validated by using a simple discrete system example through transient analysis. The flutter speed is obtained and compared to the analytical solution. Comparing to the method in which structural dynamic and fluid flow analyses are performed simultaneously, the present method is very efficient to save computational effort.

• 한국정밀공학회지
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• 제20권8호
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• pp.166-174
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• 2003

Hydrostatic bearings are widely used in precision machines due to their high motion guide accuracy, low friction and high load carrying capacity. It is very useful to estimate the moving characteristics of hydrostatic bearings in the design stage. A new method is suggested for the analysis of fluid film in hydrostatic bearings. A combined mesh of 8 node solid elements with negligible deformation resistance and spring-dashpot elements is used in conjunction with the user subroutine of ABAQUS to represent the fluid film. The mesh can be used to capture the deformation of the bearing structure as well as the varying properties of fluid film. Analysis results from the finite element model are compared with theoretical solutions, results from FLUENT analysis and some previous works. With this method, static and dynamic analyses of the system containing the bearings can be performed efficiently.

• 한국정밀공학회지
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• 제20권6호
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• pp.105-112
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• 2003

This paper presents the numerical design technology of a passive orifice fluid damper system especially for the characteristics between the damper piston velocity and the damping force. Numerical analysis with the visual interfacial modeling technique was applied into the analysis of the damper system's dynamics. A prototype orifice fluid damper was manufactured and experimentally tested to validate the numerical simulation results. The performances of various damper system schemes were investigated based on the verified numerical simulation model of orifice fluid damper.

• Structural Engineering and Mechanics
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• 제24권6호
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• pp.683-698
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• 2006

The accurate dynamic analysis of concrete arch dams relies heavily on employing a three-dimensional semi-infinite fluid element. The usual method for calculating the impedance matrix of this fluid hyper-element is dependent on the solution of a complex eigen-value problem for each frequency. In the present study, an efficient procedure is proposed which simplifies this procedure amazingly, and results in great computational time saving. Moreover, the accuracy of this technique is examined thoroughly and it is concluded that efficient procedure is incredibly accurate under all practical conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.442-447
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• 2008

This paper presents a new approach to simulate fluid-solid interaction problems involving non-matching interfaces. The coupling between fluid and solid domains with dissimilar finite element meshes consisting of 4-node quadrilateral elements is achieved by using the interface element method (IEM). Conditions of compatibility between fluid and solid meshes are satisfied exactly by introducing the interface elements defined on interfacing regions. Importantly, a consistent transfer of loads through matching interface element meshes guarantees the present method to be an efficient approach of the solution strategy to fluid-solid interaction problems. An arbitrary Lagrangian-Eulerian (ALE) description is adopted for the fluid domain, while for the solid domain an updated Lagrangian formulation is considered to accommodate finite deformations of an elastic structure. The stabilized equal order velocity-pressure elements for incompressible flows are used in the motion of fluids. Fully coupled equations are solved simultaneously in a single computational domain. Numerical results are presented for fluid-solid interaction problems involving nonmatching interfaces to demonstrate the effectiveness of the methodology.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.1077-1082
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• 2004

It is well known that the pipe will be unstable if the fluid velocity is higher than critical velocity. But even if the velocity of the fluid below the critical velocity, resonance will be caused by pulsation of the fluid. So, many people has studied about the piping system vibration due to a fluid pulsation. But almost guess that fluid has only one hamonic pulsation. Actually, like this case is rare quite. So, in this paper, we consider the vibration analysis of a pipe conveying fluid with several harmonic pulsations and compare the result which considers one hamonic pulsation with the result which considers several harmonic pulsations. And we verify the result in time domain again.

• 한국해양공학회지
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• 제31권5호
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• pp.352-356
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• 2017

We performed thermal and structural analyses to evaluate the structural integrity of a semi-metal gasket for a flange with increases in the internal fluid temperature and pressure using a commercial FEA program. As a thermal analysis result, the temperature distribution of the gasket body increased with an increase in the internal fluid temperature until the maximum fluid temperature of $600^{\circ}C$. In addition, the structural analysis showed that contact pressures of more than 35 MPa occurred uniformly in the graphite seal regions. It was found that no fluid leakage occurred under the load conditions for the structural analysis because the contact pressure in the graphite seal region was greater than the maximum internal fluid pressure of 35 MPa. Therefore, we demonstrated the structural integrity of the semi-metal gasket by performing the thermal and structure analyses under the maximum fluid temperature of $600^{\circ}C$ and the internal fluid pressure of 35 MPa.