• Steel and Composite Structures
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• 제11권5호
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• pp.423-434
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• 2011

Tongwamen Bridge is a critical link between Dongmen Island and the land in Shipu town, Zhejiang province, China. It is a 238 m span, half-through, concrete-filled steel tubular (CFST) X-type arch bridge. The width of the deck is only 10 m, yielding a width-to-span ratio of 1/23.8. The plane truss type section rib was adopted, which made of two CFST chords and web member system. The lateral stability is the key issue to this bridge. However, the existing researches on Tongwamen Bridge's lateral stability are all the deterministic structural analysis. In this paper, a new strategy for positioning sampling points of the response surface method (RSM), based on the composite method combining RSM with geometric method for structural reliability analysis, is employed to obtain the reliability index of lateral stability. In addition the correlated parameters were discussed in detail to find the major factors. According to the analysis results, increasing the stiff of lateral braces between the arch ribs and setting the proper inward-incline degree of the arch rib can enhance obviously the reliability of lateral stability. Moreover, the deck action of non-orienting force is less than the two factors above. The calculated results indicate that the arch ribs are safe enough to keep excellent stability, and it provides the foundation that the plane truss rib would be a competitive solution for a long-span, narrow, CFST arch bridge.

• 한국해안·해양공학회논문집
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• 제26권1호
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• pp.33-40
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• 2014

극한 해양 환경하중을 고려한 해상풍력터빈 지지구조물에 대한 신뢰성 해석을 수행하였다. 신뢰성 해석을 위한 한계상태함수는 mud-line에서 지지구조물의 동적응답으로 정의되며, 동적응답은 정적응답과 동적응답계수의 곱으로 정의된다. 동적응답계수는 설계조건에서의 동적 시간이력응답을 분석하여 구할 수 있다. 허브(Hub) 위치에 작용하는 추력은 GH_Bladed를 사용하여 계산하였으며, 정적하중으로 적용하였다. 동적응답계수는 대수정규분포, 지반물성 중 내부마찰각은 상한과 하한이 결정된 베타분포이며, 그 외 설계변수는 정규분포 확률변수로 취급되었다. mud-line 에서의 동적응답을 통해 정의된 한계상태함수에 따라 일계신뢰도법(First order reliability method, FORM)을 사용하여 해상풍력터빈 지지구조물의 신뢰도지수를 산정하였다.

• 한국유체기계학회 논문집
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• 제15권3호
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• pp.39-45
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• 2012

In this study, optimization of the impeller and design of volute were carried out in order to improve the performance of a centrifugal pump. Design parameters from vane plane development for impeller design were selected, and effect of the design parameters on the performance of the pump was analyzed by using Response Surface Methodology(RSM) to optimized impeller. In addition, total pump design method was suggested by designing volute which was suitable for the optimized impeller through volute design where Stepanoff theory was applied and numerical analysis.

• Journal of Magnetics
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• 제15권2호
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• pp.74-77
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• 2010

This paper deals with optimum design criteria for maximum torque density & minimum torque ripple of a Flux Switching Motor (FSM) using response surface methodology (RSM) & finite element method (FEM). The focus of this paper is to find a design solution through the comparison of torque density and torque ripple which vary with rotor shape. And then, a central composite design (CCD) mixed resolution was introduced and analysis of variance (ANOVA) was conducted to determine the significance of the fitted regression model. The proposed procedure allows one to define the rotor dimensions, starting from an existing motor or a preliminary design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1210-1211
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• 2011

The inherent drawback of iron-core type permanent magnet linear synchronous motor (PMLSM) is detent force that is dependent on several major factors such as PM length, slot clearance, and skewing. To minimize the detent force, this paper proposes a structure optimization using the combination computation of two dimensional (2-D) finite element analysis (FEA) and response surface methodology (RSM). The RSM, that is a collection of the statistical and mathematical techniques, is utilized to predict the global optimal solution based on the FEA calculated results of the detect forces for different combinations of factors. With the help of the combination computation the high capacity iron-core type PMLSM with more than 12000 N propulsion forces only contains less than 3 N detent forces.

• 한국유체기계학회 논문집
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• 제17권3호
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• pp.5-12
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• 2014

This paper presents a design optimization for meridional profile and blade angle ${\theta}$ of a centrifugal compressor with DOE (design of experiments) and RSM (response surface method). Control points of the $3^{rd}$ order Bezier curve are used for design parameters and specific overall efficiency is used as object function. The response surface function shows good agreement with the 3D computational results. Three different optimized designs are proposed and compared with reference design at design point and off-design point. Contours of relative Mach number, static entropy, and total pressure are analyzed for improvement of performance by optimization. Off-design performance analysis is conducted by total pressure and efficiency.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.777-778
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• 2006

This paper deals with the optimum rotor design approach about the multi-layer design of the buried magnets in an Interior Permanent Magnet Synchronous Motor (IPMSM), on the efficiency improvement by using Response Surface Methodology (RSM). In the multi-layer design of the prototype 15kw IPMSM, the constant amount of buried PM is split from the single-layer into double-layer design for improving the efficiency characteristics. The optimum double-layer rotor structure is built with the help of RSM analysis. The improvement of IPMSM efficiency is verified by the Finite Element Method (FEM) results comparison with the prototype single-layer IPMSM.

• 한국유체기계학회 논문집
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• 제11권2호
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• pp.38-45
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• 2008

This study presents a numerical procedure to optimize the compressor design to increase the surge margin of compressor with response surface method (RSM). The Box-Behnken design method is used to reduce the number of calculation for fitting the second-order response surface. In order to consider the increase of surge margin during numerical optimization without any calculation at the surge point, the slope of compressor characteristic curve at the design point is suggested as an objective function in the present optimization problem. Mean line performance analysis method is used to get the design and off-design characteristic curves of centrifugal compressor. The impeller exit angle, impeller exit height and impeller radius are chosen as design variables. The optimum shapes show the increase of surge margin for the surge margin optimization and increase of efficiency for the efficiency optimization in comparison with an initial shape.

• 한국자기학회지
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• 제20권6호
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• pp.239-243
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• 2010

본 논문은 반응표면법(Respone Surface Methodology)과 유한요소법(Finite Element Method)을 이용하여 250 kW급 견인 유도 전동기의 효율 향상을 위한 최적설계기준에 대해서 다루었다. 본 논문의 주 관점은 첫째, 회전자 형상 및 치수변화에 따른 토크 비교를 통해 설계 해를 찾는 것이다. 둘째, 중심합성법(Central Composite Design)과 결합된 해석방법이 도입되었고, 추정된 회귀모델의 적합성을 결정하기 위해 분산분석(Analysis Of Variance)이 수행되었다. 이렇게 제안된 실험 절차는 기존의 초기 모델로 부터 시작하여 회전자 형상 및 치수를 최적설계 하였다.

• 한국안전학회지
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• 제21권6호
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• pp.74-81
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• 2006

Probabilistic Risk Assessment considering statistically random variables is performed for the preliminary design of a Arch Bridge. Component reliabilities of girders have been evaluated using the response surfaces of the design variables at the selected critical sections based on the maximum shear and negative moment locations. Response Surface Method(RSM) is successfully applied for reliability analyses for this relatively small probability of failure of the complex structure, which is hard to be obtained by Monte-Carlo Simulations or by First Order Second Moment Method that can not easily calculate the derivative terms of implicit limit state functions. For the analysis of system reliability, parallel resistance system composed of girders is changed into parallel series connection system. The upper and lower probabilities of failure for the structural system have been evaluated and compared with the suggested prediction method for the combination of failure modes. The suggested prediction method for the combination of failure modes reveals the unexpected combinations of element failures in significantly reduced time and efforts compared with the previous permutation method or system reliability analysis method.