• International Journal of Aeronautical and Space Sciences
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• 제8권1호
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• pp.95-104
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• 2007

A new design approach of complex geometries such as wing/body configuration is arranged by using overset mesh techniques under large scale computing environment. For an in-depth study of the flow physics and highly accurate design, several special overlapped structured blocks such as collar grid, tip-cap grid, and etc. which are commonly used in refined drag prediction are adopted to consider the applicability of the present design tools to practical problems. Various pre- and post-processing techniques for overset flow analysis and sensitivity analysis are devised or implemented to resolve overset mesh techniques into the design optimization problem based on Gradient Based Optimization Method (GBOM). In the pre-processing, the convergence characteristics of the flow solver and sensitivity analysis are improved by overlap optimization method. Moreover, a new post-processing method, Spline-Boundary Intersecting Grid (S-BIG) scheme, is proposed by considering the ratio of cell area for more refined prediction of aerodynamic coefficients and efficient evaluation of their sensitivities under parallel computing environment. With respect to the sensitivity analysis, discrete adjoint formulations for overset boundary conditions are derived by a full hand-differentiation. A smooth geometric modification on the overlapped surface boundaries and evaluation of grid sensitivities can be performed by mapping from planform coordinate to the surface meshes with Hicks-Henne function. Careful design works for the drag minimization problems of a transonic wing and a wing/body configuration are performed by using the newly-developed and -applied overset mesh techniques. The results from design applications demonstrate the capability of the present design approach successfully.

• 한국전산구조공학회논문집
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• 제31권3호
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• pp.155-163
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• 2018

본 논문은 아이소-지오메트릭 해석에서 h-세분화를 이용한 국부 세분화법과 이에 따른 설계 민감도 해석의 방법론을 연구하였다. 다중 조밀도 방식을 이용하여 경계면에서 변위 적합조건을 만족하였고, 기존의 아이소-지오메트릭 해석의 텐서곱으로 인해 발생하는 원치 않는 자유도 증가의 문제를 극복하였다. 해석에서의 변위 적합조건과 마찬가지로, 설계 민감도 해석에서도 변위 결과와 마찬가지로 똑같은 적합조건을 만족하도록 하는 방법론을 제시하였다. 수치 예제를 통하여 본 방법론의 효율성을 입증하였고, 특별히 응력 집중 문제에서의 결과와 민감도 값을 비교하며 경계면에서의 적합조건을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.755-756
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• 2010

• 한국가구학회지
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• 제25권4호
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• pp.338-344
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• 2014

Modern furniture design is advancing by putting value on individual sensitivity. Accordingly, this study will focus on optical art, which can give various changes in people's sensitivity. Optical art was actively applied in various fields of image, photograph, fashion, textile, accessory and interior from the 1950s till the 1960s. Optical art realized by Victor Vasarely (1908~) opened a new trend in art by accurately realizing concise and precise expressions. This study analyzed the impact of pattern expression on sensitivity in optical art and suggested a method, which can spatiotemporally maximize the emotional change by combining optical art with the form of furniture. Modern furniture design is changing toward the direction of fitting to the propensity and emotional taste of an individual. Accordingly, this study analyzed the emotional expression felt in the furniture modeling works featured by concise, straight and standardized rectangular shape. Based on the result of analysis, this study would like to suggest a method to utilize optical pattern as a means for emotional design, with which people are able to perform various emotional expressions while keeping the function and form of furniture.

• 한국자기학회지
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• 제10권2호
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• pp.93-98
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• 2000

자기 광학 공간 광 변조기의 화소의 자화를 반전시키기 위하여 사용하는 드라이브 라인의 형상을 컴퓨터 시뮬레이션을 통하여 설계하고, 연자성막을 도입함으로써 화소 반전에 필요한 최소 전류와 소비 전력을 기존의 드라이브 라인에 비하여 약 3배 감소시킬 수 있었으며, 드라이브 라인을 묻지 않고, 화소를 덮는 반사막(드라이브 라인)의 면적을 크게 하여 광효율을 2.2배 증가시키고, 제조공정을 대폭 단순화시킬 수 있는 드라이브 라인의 형상을 제시했다.

• 한국실내디자인학회논문집
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• 제40호
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• pp.139-148
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• 2003

For lighting design in such diverse structures, we need lots of considerations, such as use and characteristics of the structure, harmony with its surroundings, and the function and type of lighting to be installed. The structural characteristics is determined by its shape and several vertical and horizontal factors based on the shape, which can be focused on at day time by shading, the surface structure, the quality of the surface and the color. On the other hand, they can be at night hidden in the darkness or enforced strongly by the effect of the lighting. In this paper, correlation between the ways of lighting and building facade types according to vocabularies for sensitivity is explored based upon an analysis of building facades for small-scale commerce which plays an important role in cityscape lighting design. It is considered that categorization of types of building facades, presented in this article, and the classification system of exterior lighting methods can be useful in planning lighting. And the process of the study is thought to be able to present a method about the exterior lighting planning. Furthermore, computer simulation on the bases of the correlation model of the lighting methods related to vocabularies for sensitivity about the building facade types is expected to be data and means which can be a great help for designers to predict various results quickly.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.571-576
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• 2007

This study presents stiffness-based optimal design to control quantitatively lateral drift of frame-shear wall structures subject to seismic loads. To this end, lateral drift constraints are established by introducing approximation concept that preserves the generality of the mathematical programming and can efficiently solve large scale problems. Also, the relationships of sectional properties are established to reduce the number of design variables and resizing technique of member is developed under the 'constant-shape' assumption. Specifically, the methodology of dynamic displacement sensitivity analysis is developed to formulate the approximated lateral displacement constraints. The 12 story frame-shear wall structural models is considered to illustrate the features of dynamic stiffness-based optimal design technique proposed in this study.

• 대한기계학회논문집
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• 제11권1호
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• pp.82-87
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• 1987

본 논문에서는 열전달문제 역시 변분형으로 전환될 수 있음에 착안하여 전미 분 개념을 도입해서 전도와 대류가 있는 열전달모델에서 주어진 면적 제한조건을 만족 시키며 지정된 경계에서의 온도가 주어진 온도에 가장 근접할 수 있는 모델의 형상을 찾는 방법을 연구하였다. 어떤 물질의 열전달 상태를 바꾸어 경계에서의 온도를 원 하는 바대로 조정하는 문제는 실제 공정에서 중요한 경우가 많다.해석시 열전달 상 태 방정식과 adjoint식은 6절점 삼각형 등계수 요소의 유한 요소법을 이용하여 해석하 였다.설계민감도의 정확한 계산을 위해서는 임의의 형상변화에 따른 경계에서의 수 치적분이 정확해야 하므로 경계를 곡선으로 표시할 수 있는 등계수 요소가 필요하다. 설계 민감도 해석이 진행된 후에는 최적화 기법의 하나인 미분벡터 투영법(Gradient Projection Method)을 사용하여 최적화를 시도했다. 최적설계 과정중 매번 계산결과 에 의해 형상의 변화가 진행되므로 그때마다 유한 요소 모델을 적절히 변화시켜 주어 야 한다. 모델의 경계는 3차함수로 근사화하여 형상이 부드러운 곡선이 되도록 했 으며 설계변수는 근사화한 3차함수를 결정할 수 있도록 정하면 되나 본 연구에서는 모 델의 변화에 따른 y좌표의 변화는 없다고 가정하여 모델경계의 세점을 취해 그 점들의 x좌표를 설계변수로 했다.

• 대한기계학회논문집B
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• 제28권3호
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• pp.296-303
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• 2004

The heat and flow characteristics in a single-phase parallel-flow heat exchanger was examined numerically to obtain its optimal shape. A response surface method was introduced to approximately predict its performance with respect to the design parameters over the design domain. The inflow/outflow angle of the working fluid, the location of inlet/outlet, the protruding height of flat tube and the height of header were chosen as a design parameter The evaluation of the relative importance of the design parameters was performed based on a sensitivity analysis. An efficiency index was used as an evaluation characteristics value to simultaneously consider both the heat transfer and the pressure drop. The efficiency index of the optimum model, compared to that of the base model, was increased by 9.3%.

• 대한기계학회논문집
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• 제19권1호
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• pp.301-309
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• 1995

Shape optimal design of an excavator boom to minimize weight can be formulated as a nonlinear programming problem with an automesh refinement carried out by using the finite element method. The design variables are the radii and the coordinates of the circle to describe the excavator boundary shape. In addition to the displacement and stress constraints, geometric constraints are imposed such that the nodes cannot cross the certain range. The optimum design is obtained by using the PLBA nonlinear programming code. The sensitivity derivatives are calculated using the semi-analytical scheme. Numerical results of an excavator boom show potential for weight reduction of 4.4%(65.6 kgf) when considering the displacement, stress and geometric constraints.