• 한국해양공학회지
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• 제23권6호
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• pp.7-11
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• 2009

The dynamic responses and drift forces in waves of a floating circular fish cage are analyzed considering hydroelastic effects. The method of generalized mode is used to calculate the hydroelastic responses of the floater of cage. The elastic mode shapes, generalized mass, and stiffness in dry mode are evaluated by using a structural analysis code. The higher-order boundary element method is adopted to analyze the interaction between fluid and deformable structure. Some results of vertical motions and drift forces are shown and compared with those for a rigid body.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.19-25
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• 2001

In metal cutting, chatter is an unstable cutting phenomenon which is due to the interaction of the dynamics of the chip removal process and the structural dynamics of machine tool. When chatter occurs, it reduces tool life and results in poor surface roughness and low productivity of the machining process. In this study, the experiments have been conducted to investigate phenomenon of the chatter in CNC lathe without cutting fluid. In the experiments, two accelerometers were attached at the tail stock and tool holder and the signals were caught. In order to observe the effect of chatter on the surface roughness profiles, surface roughness profiles were generated under the ideal condition and the occurrence of the chatter based on the surface simulation model using surface-shaping system. Finally, the result of experiment and simulation have been compared.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.51-56
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• 2017

This paper presents an approach of predicting the radiated noise due to the structural vibration by internal harmonic forces using the doubly asymptotic approximation (DAA). Acoustic transfer vector is derived from the Helmholtz integral equation and the fluid-structure interaction relation of DAA. Numerical results and analytical results of radiated noise for a cylindrical shell were compared and showed that they were consistent in most of frequencies and radiation directions, but showed errors in some radiated directions in the mid-frequency region. Despite these errors, the prediction method will be suitable for practical radiated noise prediction.

• 한국공작기계학회논문집
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• 제12권6호
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• pp.84-91
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• 2003

In metal cutting operation, it is very important that predict cutting force and work surface. Vibration is an unstable cutting phenomenon which is due to the interaction of the dynamics of the chip removal process and the structural dynamics of machine tool. When vibration on, it reduces tool life, results in poor surface roughness and low productivity of the machining process. In this study, the experiments were conducted in machining center without cutting fluid to investigate the phenomenon of vibration. In the experiments, accelerometers were set up at the tail stock and tool holder and signals were picked up. Surface roughness profiles are generated under the ideal condition and the occurrence of vibration based on the surface shaping simulation model.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.184-189
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• 2003

In metal cutting operation, it is very important that predict cutting force and work surface. Vibration is an unstable cutting phenomenon which is due to the interaction of the dynamics of the chip removal process and the structural dynamics of machine tool. when Vibration occurs, it reduces tool life, results in poor surface roughness and low productivity of the machining process. In this study, the experiments were conducted in machining center without cutting fluid to investigated phenomenon of the Vibration. In the experiments, accelerometers were set up at the tail stock and tool holder and the signals were picked up. In this paper, surface roughness profiles will be generated under the ideal condition and the occurrence of the vibration based on the surface shaping simulation model.

• Structural Engineering and Mechanics
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• 제13권4호
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• pp.355-368
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• 2002

In this paper, we address the numerical investigation on the effect of liquid compressibility onto the natural frequency of liquid-filled containers. Traditionally the liquid motion has been treated as an ideal fluid motion. However, from the numerical experiments for the axisymmetrical free-vibration of cylindrical liquid-storage tanks, we found that the relative difference in natural frequencies between ideal and compressible motions becomes remarkable, as the slenderness of tank or the relative liquid-fill height becomes larger. Therefore, in such cases of dynamic systems, the liquid compressibility becomes an important parameter, for the accurate vibration analysis. For the free-vibration analysis of compressible liquid-structure interaction we employed the coupled finite element formulation expressed in terms of the acoustic wave pressure and the structure deformation.

• Ocean Systems Engineering
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• 제3권2호
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• pp.149-165
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• 2013

Tension leg platforms (TLP's) are highly nonlinear due to large structural displacements and fluid motion-structure interaction. Therefore, the nonlinear dynamic response of TLP's under hydrodynamic wave loading is necessary to determine their deformations and dynamic characteristics. In this paper, a numerical study using modified Morison Equation was carried out in the time domain to investigate the influence of nonlinearities due to hydrodynamic forces and the coupling effect between all degrees of freedom on the dynamic behavior of a TLP. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables and the nonlinear equations of motion were solved utilizing Newmark's beta integration scheme. The effect of wave characteristics was considered.

• Structural Engineering and Mechanics
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• 제65권1호
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• pp.69-79
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• 2018

This paper is devoted to two new techniques for free vibration analysis of concrete arch dam-reservoir systems. The proposed schemes are quadratic ideal-coupled eigen-problems, which can solve the originally non-symmetric eigen-problem of the system. To find the natural frequencies and mode shapes, a new special-purpose eigen-value solution routine is developed. Moreover, the accuracy of the proposed approach is thoroughly assessed, and it is confirmed that the new scheme is very accurate under all practical conditions. It is also concluded that both decoupled and ideal-coupled strategy proposed in the previous works can be considered as special cases of the current more general procedure.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.871-876
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• 2001

One-touch fittings are important components that can make a quick and tight connection between pneumatic pipe systems. In this study, the stress analyses with various working pressures on these one-touch fittings are carried out using finite element method. Material properties, to use the stress analyses, are measured by the universal tester and digital Vickers hardness tester. The stress analyses on the circular shell spring forced by various pressures(100, 150, 200, 250kpa) and on the main body due to the fluid-structural interaction are investigated. Results show that the stresses of one-touch fitting are concentrated to supported part of main body and the soundness of a circular shell spring with maximum pressure 250kpa was confirmed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.174-179
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• 2002

In metal cutting, Chatter is an unstable cutting phenomenon which is due to the interaction of the dynamics of the chip removal process and the structural dynamics of machine tool. when vibration and chatter occurs, it reduces tool life, results in poor surface roughness and low productivity of the machining process. In this study, the experiments were conducted in CNC lathe without cutting fluid to investigated phenomenon of the chatter, In the experiments, accelerometers were set up at the tail stock and tool holder and the signals were picked up. In order to observe the effect of chatter on the surface roughness profiles, in this paper, surface roughness profiles will be generated under the ideal condition and the occurrence of the chatter based on the surface simulation model.