• 한국공작기계학회논문집
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• 제17권1호
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• pp.106-112
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• 2008

In this paper, It does the profile measurement of the cam of diesel engine SOHC of the actual object. It uses the measurement of run-out method. This method is that the surface of the object is measured by the sensor when the object rotate, and calculated and displayed by the computer the signal which acquired by sensor. When we acquire the signals, we have two error because of motion and contacting between cam and probe. In this paper, we compensate the motion error while simply liner equation. And we have a solution that we change the figure of probe when we have a contacting error. We compared the data measuring on developed automatic cam profile measuring system with the data measured on CMM.

• 한국자동차공학회논문집
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• 제24권2호
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• pp.242-254
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• 2016

This paper is the forth investigation on the evaluation methods of flow characteristics in a steady flow bench. In the previous works, it was concluded that the assumption of the solid rotation might cause serious problems and both of the eccentricity and the velocity profile distort the flow characteristics when using the ISM at 1.75B plane. Also particle image velocimetry (PIV) measurement at this position showed that the real velocity profile was far from the assumption of ISM evaluation. In this paper, the planar velocity profiles were measure from 1.75B to 6.00B position by PIV and the characteristics were examined according to the valve angles and lifts for further investigations about the effect of the position on the velocity profile. The results show that $26^{\circ}$ valve angle is always an unique exceptional case in all aspects. If the valve angle is $21^{\circ}$ and below, the planar velocity profiles according to the lift and the position are similar to each other, however, the tangential velocity curves along with the radial direction have common tendencies up to $16^{\circ}$ angle. Also the well arranged swirl behaviors are generally observed at the position above 3.00B and the velocity contour lines come closer to the concentric circle as the valve lift increases. In addition, the gradient of tangential velocity along with the radial direction from the swirl center becomes stable and constant as the position goes downstream. Concurrently the velocity gradient is larger to the eccentric direction of the center. In the meantime the tangential velocity curves along with the radial direction are irregular and various at 1.75B, however, they become regular and reach higher level as the evaluation position goes downstream. At this time the curves of 4.50B are the best fitted to the ideal one. On the other hand in an exceptional case, $26^{\circ}$, the velocity contours are very complicated over 6mm valve lift regardless the position and the gradient increases to the opposite direction of the eccentric center. Also, 6.00B is a best fitting position in the geometrical cylinder center base. With respect to the swirl center, the distribution range of centers for 1.75B is different to that for the other positions and the eccentricities of this plane are larger regardless the valve angle. After 1.75B, there is no certain tendency in the center position change according to the valve angle and lift. Additionally, the eccentricities are not sufficiently small to neglecting the effect on ISM measurement.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.297-301
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• 2007

초음속 충동형 터빈과 같이 종횡비가 작은 경우 로터 익형은 반경방향으로 동일한 단면을 갖는 형태로 구현된다. 이 경우 터빈 로터는 터빈 동익의 프로파일 직경에 따라 설계에서 의도하지 않은 유로면적분포와 터빈 성능의 차이를 보인다. 본 연구에서는 터빈 동익 프로파일을 정의하는 직경이 터빈 성능에 미치는 영향을 고찰하기 위하여 3개의 다른 위치에서 정의된 터빈 로터에 대한 유동해석을 수행하고 결과를 고찰하였다. 계산 결과 팁에서 단면이 정의된 경우 설계에서 의도한 유로면적 변화를 보이며 다른 프로파일 직경에서 정의된 터빈에 비해 우수한 성능을 보임을 확인하였다.

• Structural Engineering and Mechanics
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• 제55권3호
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• pp.473-494
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• 2015

A graded harmonic finite element formulation based on three-dimensional elasticity theory is developed for the structural analysis of 2D functionally graded axisymmetric structures. The mechanical properties of the axisymmetric solid structures composed of two different metals and ceramics are assumed to vary in radial and axial directions according to power law variations as a function of the volume fractions of the constituents. The material properties of the graded element are calculated at the integration points. Effects of material distribution profile on the static deformation, natural frequency and dynamic response analyses of particular axisymmetric solid structures are investigated by changing the power law exponents. It is observed that the displacements, stresses and natural frequencies are severely affected by the variation of axial and radial power law exponents. Good accuracy is obtained with fewer elements in the present study since Fourier series expansion eliminates the need of finite element mesh in circumferential direction and continuous material property distribution within the elements improves accuracy without refining the mesh size in axial and radial directions.

• 천문학논총
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• 제22권3호
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• pp.75-81
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• 2007

In this study we present basic principles and features of RVI2CELL, a precise RV (radial velocity) estimation program to process stellar spectra obtained through iodine cell. RVI2CELL is very robust and fast program. The instrument profile can be modeled as a sum of Gaussian functions or a non-parametric arbitrary shape. The RV accuracy estimated by observation of a RV standard star Tau Ceti indicates about 9 m/s.

• 한국CDE학회논문집
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• 제17권5호
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• pp.312-323
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• 2012

Planetary gearing is a gear system consisting of one or more planet gears, revolving about a sun gear. While the planetary gear system has many advantages- for example, high power density, large reduction in a small volume, multiple kinematic combinations, pure torsional reactions, and coaxial shafting, it has not been widely used because of its high bearing loads, inaccessibility, and design complexity. It is also necessary to shift several pairs of gear profiles at a same time. Therefore, designing profile shifted planetary gear system is a difficult and know-how dependent job. This study provides a practical solution to design a profile shifted gear system by the procedural design scheme, and proposes a bearing integrated structure of the dual stage profile shifted gear system with a robust output end. A dual stage profile shifted gear system with the bearing integrated structure is manufactured by the proposed design scheme in this study. This gear system is verified that it is good enough to commercialize, because it has high performance with high gear ratio and robust output end against axial and radial directional runouts in a small space.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.143-144
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• 2009

• 천문학회보
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• 제33권1호
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• pp.34.1-34.1
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• 2008

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권1호
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• pp.18.1-18.1
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• 2008

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.17-20
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• 2007

연소실내 형성되는 접선방향 음향 모드의 감쇠를 위해 장착되는 공명기의 반경 방향 위치 효과에 대해 실험적으로 연구하였다. 반파장 공명기를 채택하였고, 상온에서 선형 음향 실험을 수행하였다. 감쇠 대상 음향 모드에 대해 공명기가 최적의 길이를 갖는 경우에는, 반경 방향 위치의 증가에 따라 음향 감쇠 효과가 증가하였다. 또한, 반경방향으로의 감쇠 인자의 변화 추이는 감쇠시키고자 하는 음향 모드의 진폭 변화 추이와 유사하였다. 장착 위치가 장착변의 중심에 접근할수록 음향 감쇠 효과가 감소할 뿐만 아니라 분사기 길이와의 상관성도 감소하였다. 공명기가 비최적 길이를 갖는 경우에는, 반경 방향 위치 효과가 거의 나타나지 않아 위치와 무관한 감쇠 인자값을 관찰할 수 있었다.