• 한국자동차공학회논문집
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• 제3권1호
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• pp.97-107
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• 1995

Global postbuckling analysis is accomplished for one-dimensional and two-dimensional delaminations. A new finite element model, which can be used to model the global postbuckling analysis of one-dimensional and two-dimensional delaminations, is presented. In order to calculate the strain energy release rate, geometrically nonlinear analysis is accomplished, and the incremental crack closure technique is introduced. To check the effectiveness of the finite element models and the incremental crack closure technique, the simplified closed-form sloution for a through-the-width delamination with plane strain condition is derived and compared with the finite element result. The finite element results show good agreement with the closed-foul1 solutions. The present method was extended to calculate the strain energy release rate for two-dimensional delamination. For a symmetric circular delamination, the strain energy release rate shows great variation along the delamination front. and the delamination growth appears to occur perpendicular to the loading direction.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.22-27
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• 1993

The finite element method is applied to analyze the mechanism of metal cutting. This paper introduces some effects, such constitutive deformation laws of workpiece material, friction of tool-chip contact interfaces, tool rake angles and also simulate the cutting process, chip formation and geometry, tool-chip contact, reaction force of tool, cutting temperature. Under the usual [lane strain assumption, quasi-static analysis were performed with variation of tool-chip interface friction coefficients and rake angles. In this analysis, various cutting speeds and depth of cut are adopted. Some cutting parameters are affected to cutting force, plastic deformation of chip, shear plane angle, chip thickness and tool-chip contact length and reaction forces on tool. Cutting temperature and Thermal behavior. Several aspects of the metal cutting process predicted by the finite element analysis provide information about tool shape design and optimal cutting conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.601-602
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• 2002

Numerical simulation using well-known commercial software Fine/Turbo is applied to the analysis of the aerodynamic performance for the supersonic turbine system with partial admission nozzle. Calculation was performed for coupled system of nozzle and blades using mixing plane method. In addition, calculations were also performed for the blades alone to investigate the effect of the performance variation with blade profile. These computational results are compared with the experiments. The agreement between the prediction and the experiment was found to be satisfactory..

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 봄 학술발표회 논문집
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• pp.43-47
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• 1991

3차원 자유형상 구조물인 선박, 비행체, 자동차 등의 최적형상 결정에 관한 구조해석을 위해서는 원하는 설계조건을 만족시키는 범위내에서 자유형상 구조물의 다양한 형상의 정의와 비교가 필요하다. 본 연구에서는 형상계수를 이용한 3차원 자유형상 구조물의 정의와 정의된 구조물의 체계적인 변화 및 구조해석을 위한 기하학적 형상정보의 도출을 시도하고, 이의 검증을 위해 선정한 자유형상 모델을 통해 이 방법의 유용성을 조사했다.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권8호
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• pp.367-375
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• 2001

In Underwater Flight Vehicle depth control system, the followings must be required. First, it needs robust performance which can get over modeling error, parameter variation and disturbance. Second, it needs accurate performance which have small overshoot phenomenon and steady state error to avoid colliding with ground surface or obstacles. Third, it needs continuous control input to reduce the acoustic noise and propulsion energy consumption. Finally, it needs interpolation method which can sole the speed dependency problem of controller parameters. To solve these problems, we propose a depth control method using Fuzzy Sliding Mode Controller with feedforward control-plane bias term and Neural Network Interpolator. Simulation results show the proposed method has robust and accurate control performance by the continuous control input and has no speed dependency problem.

• 신재생에너지
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• 제4권3호
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• pp.36-44
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• 2008

This paper discusses about the mathematical modelling of a new conceptual shape of horizontal axis wind turbine. The geometrical characteristic of wind turbine is studied for the variation of azimuthal angles and elevation angles. The projecting trajectories of Cuban-8 blade due to rotation are analyzed on the each plane in the Cartesian coordinate system. Trajectories show several interesting graphical patterns since the geometrical shape is complicated with the rotational motion of two twisted circumferential blades with elevation angles.

• 한국측량학회지
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• 제3권2호
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• pp.18-31
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• 1985

본 연구는 FEM에 의한 3 변측양의 조정을 해석하는데 그 목적이 있으며, FEM은 대상물의 예위 및 변동의 문제를 해석하는 수치해석이다. 본 연구에서는 평면 3 각망과 평면구조물과의 형상과 해석이 비슷하기 때문에 FEM의 기법을 3변측양조정에 이용하였다. 따라서 본 연구에서는 3 변측양조정에 FEM과 조건방정식방법을 적용하여 그들의 정밀도와 특성을 고찰하였다.

• 전산구조공학
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• 제5권2호
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• pp.79-85
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• 1992

3차원 자유형상 구조물인 선박, 비행체, 자동차 등의 최적형상 결정에 관한 구조해석을 위해서는 원하는 설계조건을 만족시키는 범위내에서 자유형상 구조물의 다양한 형상의 정의와 비교가 필요하다. 본 연구에서는 형상계수를 이용한 3차원 자유형상 구조물의 정의와 체계적인 변화 및 구조해석을 위한 기하학적 형상정보의 도출을 시도하고, 이의 검증을 위해 선정한 자유형상 모델을 통해 이 방법의 유용성을 조사했다.

• 전기학회논문지
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• 제56권11호
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• pp.1995-1997
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• 2007

In this paper we propose a wavelength-switchable fiber ring laser that employs a polarization-dependent fiber band stop filter. The fiber filter was fabricated by inscribing a long-period fiber grating on a high birefringent fiber. Dual-wavelength switching operation was accomplished by controlling the rotatable linear polarizer which rotated the polarization plane of the light circulating through the fiber laser cavity. The amplitude variation of both laser lines was measured to be less than 0.5 dB and the signal-to-amplified spontaneous emission ratio was more than 55 dB.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.284-285
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• 2007

In this paper, we present the effect on a novel transmission line filter response by the etch hole position on the suspended ground and the residue on the resonator under ground plane. We defined the etch hole offset as the distance from the sidewall of the suspended ground to the nearest side of the etch holes. We simulated new filter responses to reflect the real value of the changed etch hole offset caused by characteristics of negative photoresist. Return loss is distorted by the residue on the center conductor remained after sacrificial layer removing. By comparison of simulation and measurements, we concluded the residue on the resonator distorted the RF response worse than etch hole offset variation did.