• 대한기계학회논문집A
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• 제39권2호
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• pp.169-177
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• 2015

내접형 기어펌프에 사용되는 지로터의 경우, 소결 공정기술의 발달로 복잡한 형상의 가공이 용이하며 내구성과 소형화의 장점이 있으나, 자동차의 연비효율 개선을 위한 유량증대 및 소음저감을 위한 연구가 요구되고 있다. 본 논문에서는 기존의 병진이동에 의한 지로터 치형의 형상조합 알고리즘이 가지는 형상 불연속성을 개선하기 위하여 회전이동 및 병진이동을 이용한 형상조합 알고리즘을 개발하였으며, 이를 토대로 개발된 설계 프로그램을 이용하여 3-타원이 조합된 경우와 타원 1-인벌루트-타원 2 이조합된 경우에 대해 치형형상을 도출하고, 형상에 따른 로터의 주요성능(유량, 유량맥동, 미끄럼률 및 압력각)을 계산하였다. 해석결과를 토대로 조합된 치형형상에 대한 최적설계를 수행하였으며, 기존 치형과의 성능 비교를 통하여 설계의 타당성을 검증하였다.

• 한국화재소방학회논문지
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• 제29권5호
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• pp.51-56
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• 2015

본 연구에서는 설계프로그램의 공학적 분석의 수단 또는 가치공학 측면에서 원가절감 등의 목적으로 최적설계 이론과 공학적 이론을 접목시킨 최적설계법을 가스계 소화설비 중 청정소화약제 소화설비의 약제방출량 산출에 응용하였다. 청정소화약제 소화설비의 설계이론과 최적설계 이론을 바탕으로 약제방출량을 최적화시킬 수 있는 최적설계인자를 도출하였고, 이를 설계인자로 구축된 소화설비의 소화성능시험으로 최적설계법의 적합성 여부를 검증함으로써 다른 소화설비에도 최적설계법을 접목할 수 있는 기틀을 마련하였다. 방출헤드의 약제방출량 최적화는 방출헤드 및 배관의 내경, 약제도달시간, 유량과 압력변화 등의 소화약제 유동특성에 대한 제한조건에 의해 결정됨을 확인하였고, 방출헤드의 방출압력과 약제도달시간의 편차는 배관의 압력변화만큼 발생되고 상관관계가 있음을 알 수 있었다.

• 한국정밀공학회지
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• 제10권3호
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• pp.87-96
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• 1993

In this study, the peak stress of a fuillet in elastic structure was optimized to have minimum value by using quadratic isoparametric element. The method of auomatic gridding was also developed along with shape algorithm and design element technique was adopted in selecting design variables. The computer program developed was combined with the Hooke-Jeeves direct algorithm of optimization techniques in order to minimize the peak stress of the fillet. The imployment of design element technique significantly cut down computer time by the reduction in design variables, and the opitmum fillet shape with uniform minimum stress was obtained by varying design variables along x and y directions in improving the shape compared to other results. By using automatic gridding, in which Bezier surfaces and Coons surfaces of cubic interpolation were employed, the irregular boundary was removed resulting in smoother anbd more accurate fillet shape possessing uniform minimum stress.

• 한국유체기계학회 논문집
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• 제15권6호
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• pp.18-24
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• 2012

This study simulated the operation of a steam injected gas turbine combined heat and power (CHP) system. A full off-design analysis was carried out to examine the change in the turbine blade temperature caused by steam injection. The prediction of turbine blade temperature was performed for the operating modes suggested in the previous study where the limitation of compressor surge margin reduction was analyzed in the steam injected gas turbine. It was found that both the fully injected and partially injected operations suggested in the previous study would cause the blade temperature to exceed that of the pure CHP operation and the under-firing operation would provide too low blade temperature. An optimal operation was proposed where both the turbine inlet temperature and the injection amount were modulated to keep both the reference turbine blade temperature and the minimum compressor surge margin. The modulation was intended to maintain a stable compressor operation and turbine life. It was shown that the optimal operation would provide a larger power output than the under-firing operation and a higher efficiency than the original partially injected operation.

• Smart Structures and Systems
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• 제6권7호
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• pp.767-792
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• 2010

In this paper, the optimal design of vibration control system for smart structures has been investigated semi-analytically via the optimization of geometric parameters like the placements and sizes of piezoelectric sensors and actuators (S/As) bonded on the structures. The criterion based on the maximization of energy dissipation was adopted for the optimization of the control system. Based on the sensing and actuating equations, the total energy stored in the system which is used as the objective function was analytically derived with design variables explicitly presented. Two cases of single and combined vibration modes were addressed for a simply supported beam and a simply supported cylindrical shell. For single vibration mode, the optimal distributions of the piezoelectric S/As could be obtained analytically. However, the Sequential Quadratic Programming (SQP) method has to be employed to solve those which violated the prescribed constraints and to solve the case of combined vibration modes. The results of three examples, which include a simply supported beam, a simply supported cylindrical shell and a simply supported plate, showed good agreement with those obtained by the Genetic Algorithm (GA) method. Moreover, in comparison with the GA method, the proposed method is more effective in obtaining better optimization results and is much more efficient in terms of computation time.

• 한국소음진동공학회논문집
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• 제12권10호
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• pp.773-784
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• 2002

This paper proposes an optimal design to improve the performance of the intake system by reducing the noise. We adapt the Taguchi method and column merging method for the above design. At the first stage of the design, the length and radius of each component of the current intake system are selected as control factors. Then the $L^{18}$ table of orthogonal array is used to get the effective main factors. At the second stage, the $L^{16}$ table of orthogonal array and the column merging method is combined to analyze subdivided significant factors. We know that the robust design with the column merging method provides better design for noise of intake system than the robust design itself.

• 한국통신학회논문지
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• 제28권5C호
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• pp.468-475
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• 2003

본 논문에서는 패턴생성을 위한 최적의 이진 위상 컴퓨터형성 홀로그램을 설계하기 위해 합성된 SA알고리듬 및 유전 알고리듬을 이용하였다. 제안된 방법의 탐색과정에서 sGA를 사용하여 BPCGH를 생성하고. 결과 홀로그램 패턴을 SA 알고리듬의 초기 랜덤 투과함수로 이용하여 최적의 BPCGH를 설계하였다. 컴퓨터 시뮬레이션에서 독립적으로 사용된 SA 알고리듬과 유전 알고리듬을 비교한 결과 제안한 알고리듬이 회절 효율이 향상된 것을 확인할 수 있었다.

• Geomechanics and Engineering
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• 제5권6호
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• pp.519-540
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• 2013

This paper presents an optimal design method for determining pile lengths of piled raft foundations. The foundation settlement is evaluated by taking into account the raft-pile-soil interaction. The analysis of settlement is simplified by using Steinbrenner's equation. Then the total pile length is minimized under the settlement constraint. An extended sequential linear programming technique combined with an adaptive step-length algorithm of pile lengths is used to solve the optimal design problem. The accuracy of the simplified settlement analysis method and the validity of the obtained optimal solution are investigated through the comparison with the actual measurement result in existing piled raft foundations.

• Journal of Magnetics
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• 제20권2호
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• pp.161-165
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• 2015

The Permanent Magnet Brushless DC (PMBLDC) motors have been used in modern industrial factories, hazardous chemical process, modern medical devices, and especially in advanced military devices such as army drones. By considering their sensitive role in the industrial and military applications, their optimal design has a real concern. This paper proposes a method for optimal eco-design of a PMBLDC motor using improved tabu search optimization. The objective function is based on losses, volume and cost. Electrical and mechanical requirements and other limitations are combined into constraints of problem. Also, finite element analysis has been used for verifications in magnetic mode.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.972-974
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• 1993

This paper presents a new method to automatically design fuzzy logic controller(FLC). The main problems of designing FLC are how to optimally and automatically select the control rules and the parameters of membership function (MF). Cell state space algorithms (CSS), differential competitive learning (DCL) and multialyer neural network are combined in this paper to solve the problems. When the dynamical model of a control process is known. CSS can be used to generate a group of optimal input output pairs(X, Y) used by a controller. The(X, Y) then can be used to determine the FLC rules by DCL and to determine the optimal parameters of MF by DCL and to determine the optimal parameters of MF by multilayer neural network trained by BP algorithm.