• 대한기계학회논문집B
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• 제23권7호
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• pp.831-840
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• 1999

In this work, an aerothermodynamic calculation model for cooled axial flow turbine blades with trailing edge ejection is suggested and a mean line performance analysis of a turbine stage with nozzle cooling is carried out. A unique model regarding the interaction between coolant and main gas is proposed, while existing correlations are adopted to predict viscous loss and blade outflow angle. The interactions considered are the heat transfer from main gas to coolant and the temperature and pressure losses by the mixing of two streams due to the trailing edge coolant ejection. For a stator blade without ejection, trailing edge loss calculated by the trailing edge analysis is compared with that calculated by loss correlation. The effect of heat transfer effectiveness of coolant passage on the mixing loss is analyzed. For a model turbine stage with nozzle cooling, parametric analyses are carried out to investigate the effect of main design variables(coolant mass flow ratio, temperature and ejection area) on the stage performance.

• Tribology and Lubricants
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• 제26권5호
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• pp.263-271
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• 2010

The rollers of cylindrical roller bearing are axially profiled to relieve high edge stress concentration caused by mainly their finite length and by misalignment. In this paper, a numerical analysis is carried to study the EHL of misaligned (tilted) rollers with axially profiled ends. Using a finite difference method with non-uniform grids and the Newton-Raphson method, the highly nonlinear EHL problems are systematically solved. Physically consistent solutions are obtained for moderate load, material parameters and very small misalignment. For different misalignment angles, contours and sectional plots of pressure and film shape near both edge regions are compared. The asymmetric pressure distributions and film shapes show that the EHL results of finite line contacts are highly dependent upon very small amounts of roller misalignment. Especially, the effect of misalignment on the EHL pressure distribution is much higher than the film shapes.

• E2M - 전기 전자와 첨단 소재
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• 제9권8호
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• pp.783-788
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• 1996

In this paper, the high-$T_c$ , superconductor (HTS) microstrip patch antenna which is directly coupled to a microstrip transmission line is designed and the numerical solution which evaluate near electromagnetic field of HTS antenna is presented. This solution uses the interpolation function with the vector edge triangular element. The advantage of this element is the elimination of spurious solutions attributed to the lack of enforcement of the divergence condition. The results of this method have a good agreement with $TM_10$ mode in HTS microstrip patch antenna and show that the computation of resonant length considering the fringing capacitance effect at radiating edge are proper.

• 복합신소재구조학회 논문집
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• 제3권2호
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• pp.47-54
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• 2012

In this study, composite laminate cantilever type cylindrical shells with edge-stiffeners are analyzed. A versatile 4-node flat shell element which is useful for the analysis of shell structures is used. An improved flat shell element is established by the combined use of the addition of non-conforming displacement modes and the substitute shear strain fields. Two models by load conditions are considered. Load type A and B are loaded by point load at the free edge and line load respectively. A various parameter examples are presented to obtain proper stiffened length and stiffened thickness of edge-stiffeners. It is shown that the thickness of shell can be reduced minimum 30% by appropriate edge-stiffeners.

• 한국공간구조학회논문집
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• 제12권4호
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• pp.57-69
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• 2012

This study investigated the behaviors of the gabled hyperbolic paraboloid shell structure subjected to differential settlement and the horizontal displacement due to the elongation of tie rod/beam on supports. Two types of shell structure with different roof slopes are used in study; conventional type which has perimeter beams around the shell panel, and simple type which removes the edge beams along the slab edge line. The effect of the removal of edge beam under vertical or horizontal displacement on supports, and the roof slope was compared using the finite element analysis.

• 항공우주시스템공학회지
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• 제13권5호
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• pp.32-38
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• 2019

높은 후퇴각을 갖는 둥근 앞전 날개 형상은 앞전 와류에 의해 복잡한 유동 현상이 나타난다. 불안정한 방향 안정성을 갖는 무미익 플라잉윙의 제어를 위해서 플래퍼론이 사용된다. 본 연구에서는 플래퍼론이 전개된 비세장형, 둥근 앞전의 플라잉윙 형상의 전산해석을 수행하였으며 옆미끄럼각 및 플래퍼론에 대한 영향을 분석하였다. 공력계수 분석을 통해 양력과 항력계수에 대한 옆미끄럼각의 영향은 적으며 측력 및 모멘트 계수는 옆미끄럼각의 영향을 크게 받음을 알 수 있었다. 정적 안정성 분석을 통해 플래퍼론이 전개된 플라잉윙의 가로안정성과 방향안정성이 좋아졌음을 확인하였다. 또한 압력계수분포, 표면 마찰선의 관찰을 통해 앞전 와류 구조 및 거동을 분석하였다.

• 대한치과보철학회지
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• 제35권4호
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• pp.742-766
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• 1997

The purpose of this study was to determine the effect of finish line design, amount of incisal reduction, and loading condition on the stress distribution in anterior all-ceramic crowns. Three-dimensional finite element models of an incisor all-ceramic crown with 3 different finish line designs : 1) shoulder with sharp line angle 2) shoulder with rounded line angle 3) chamfer : and 2 different incisal reductions : 2mm and 4mm were developed. 300 N force with the direction of 45 degree to the long axis of the tooth was applied at 3 different positions : A) incisal 1/3, B) incisal edge, C) cervical 1/5. Stresses developed in ceramic and cement were analyzed using three-dimensional finite element method. The results were as follows : 1. Stresses were concentrated in the margin region, which were primarily compressive in the labial and tensile in the lingual. 2. Stresses were larger in the area near line angle than on the crown surface of the margin region. In case of shoulder with sharp line angle, stresses were highly concentrated in the porcelain near line angle. 3. At the interface between porcelain and cement and at the porcelain above the margin on crown surface, stresses were the highest in chamfer, and decreased in shoulder with sharp line angle and shoulder with rounded line angle, respectively. 4. At the interface between cement and abutment on crown surface, stresses were the highest in shoulder with sharp line angle, and decreased in shoulder with rounded line angle and chamfer, respectively. 5. The amount of incisal reduction had little influence on the stress distribution in all-ceramic crowns. 6. When load was applied at the incisal edge, higher stresses were developed in the margin region and the incisal edge than under the other loading conditions. 7. When load was applied at the cervical 1/5, stresses were very low as a whole.

• 한국산학기술학회논문지
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• 제14권7호
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• pp.3454-3459
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• 2013

수묵 담채화는 먹과 채색을 동시에 사용하는 예술 양식을 의미한다. 이는 동양 미술의 전통적인 기법중의 하나로 널리 알려져 있으며, 영화 및 광고 포스터 및 카메라의 다양한 특수효과 표현 등에 널리 활용된다. 본 연구에서는 컴퓨터 그래픽스 및 영상처리 기법을 기반으로, 참조된 예제 이미지의 수묵담채화 특징이 반영된 결과영상 생성 알고리즘을 제안한다. 이를 위해 우리는 크게 두 가지 단계를 거친다. 첫 번째 단계는 채색 효과 표현단계이다. 우리는 예제 영상에 나타나는 재질감을 수치적으로 분석해 결과 영상에 반영할 수 있는 질감 전이 기법을 활용하였다. 두번째는 먹선 효과의 표현이다. 우리는 예제영상의 윤곽선에서 나타나는 명도 변화 값을 고려하여 먹선 효과를 표현하였다. 우리의 알고리즘은 선택된 참조 영상에 따라 다양한 느낌의 수묵 담채 스타일의 결과를 표현할 수 있으며, 이 기법은, 다양한 콘텐츠 생성 연구에 활용 가능하다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.553-559
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• 1998

This thesis studied to evaluate the fatigue behavior and propagation of rail steel under welding line. Test of crack growth was performed by all member of rail under constant amplitude loading at the structures laboratory in Hongik University. The effect of the following parameters with initiated crack length on the bottom edge of rail were studied. Here, fracture mechanics mode is opening mode. and Testing Material is KS50N Rail. From analysis and experimented result on the three Point bending in the lab, This paper presented a effect of crack growth , shape and remaining service life. Further more, according to the variable crack length, variable section and the ratio of section the fatigue behavior and propagation were studied.

• 복식문화연구
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• 제4권3호
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• pp.373-381
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• 1996

Draping design system organized by European about 13C has been developed greatly for a long while, but for the purpose of the practical use the Dress form similar to human body has been needed. In order to make three-dimensional effect as fitting Muslin ot the Dress form. the Basic lien has to be established in Muslin and Dress form each. At this time, Shoulder-blade level is indicated from various angles : measure down 10cm from the back neck point, a quarter of the back neck point to the waist lie, the half-way point between neckline and bust line, measure down 41 inches from the back neck line, measure down 3 inches from the top edge of the muslin at center back and cross mark for neck line, and so forth. This study established the Basic line through the two ways of them (B.N.P∼B.L/2, B.N.P∼W.L/4), did tight fitting to the 5 kinds of Dress forms which ar normal type in the drop value(the difference between hip circumference and bust circumference), and acquired Basic Pattern. After the experiment, fitness are throughly investigate by statistical analysis of measurements. As a result, this study finds out that fit is proper when shoulder blade level is situated on a fourth of the back neck point to the waist line and a quarter point between back neck point and waist line, and waist dart is situated on the back center line and princess line.