하모니 서치와 시뮬레이티드 어넬링을 사용한 트러스의 단면 및 형상 최적설계

김봉익,Kim, Bong Ik 한국강구조학회 2015 韓國鋼構造學會 論文集 Vol.27 No.2

트러스구조는 대형구조물의 설계 및 시공에 편리하며, 부재의 경량화에 따른 비용의 절검 효과를 얻을 수 있는 구조물로 최근 다양한 형태의 구조물건설에 많이 사용되고 있다. 본 연구에서는 응력, 좌굴 그리고 구조물의 고유진동수 제약조건을 고려한 트러스 구조물의 단면과 형상에 대해 최적설계를 하였다. 최적설계에서 최적화기법으로 HA-SA방법을 제시하였으며, HA-SA방법은 HA 초기메모리에서 최상의 설계를 SA의 초기 설계로 하여 최적화 하는 방법이다. 예제에 사용된 트러스 구조물은 고유진동수 제약조건으로 10-bar, 72-bar, 52-bar 트러스와 응력 및 좌굴응력 제약조건으로 18-bar, 47-bar 트러스를 사용하였다. 그리고 52-bar, 18-bar, 47-bar의 경우는 트러스의 형상을 최적설계 하였다. 예제로부터 다양한 설계 제약조건하에서 여러 연구결과와 HA, SA, GA, HA-SA방법에 의한 결과를 서로 비교하여 HA-SA방법의 적용성을 입증하였다. In this paper, we present an optimization of truss structures subjected to stress, buckling, and natural frequency constraints. The main objective of the present study is to propose an efficient HA-SA algorithm for solving the truss optimization subject to multiple constraints. The procedure of hybrid HA-SA is a search method which a design values in harmony memory of harmony search are used as an initial value designs in simulated annealing search method. The efficient optimization of HA-SA is illustrated through several optimization examples. The examples of truss structures are used 10-Bar truss, 52-Bar truss (Dome), and 72-Bar truss for natural frequency constraints, and used 18-Bar truss and 47-Bar (Tower) truss for stress and buckling constraints. The optimum results are compared to those of different techniques. The numerical results are demonstrated the advantages of the HA-SA algorithm in truss optimization with multiple constraints.

유전자 알고리즘을 사용한 강구조물의 최적설계

김봉익,Kim, Bong Ik 한국강구조학회 2012 韓國鋼構造學會 論文集 Vol.24 No.6

최근에는 고층구조물이나 해양구조물(플랜트)의 경우 대부분 대형화로 설계 및 시공되고 있다. 대형구조물의 경우 주로 강재(steel)를 사용하여 설계하고 있다. 구조물 설계는 설계단계에서 최상의 부재를 선택하는 최적화를 적용함으로서 비용을 줄이는 경제적인 효과를 얻을 수 있다. 본 연구에서는 트러스와 프래임 구조물의 최적설계에 연속변수와 이산변수를 사용하여 최적화 하였고, 설계에서 사용된 이산자료는 규격화된 강재에 대한 자료와 데이터화된 이산자료를 사용하였다. 최적화는 이 모두에 적합한 이산최적화를 적용하였다. 최적화 기법으로는 유전자 알고리즘을 사용하였으며, 사용된 구조물은 10-Bar, 25-Bar 트러스와 1경간 2층, 1경간 7층 프레임 구조물이다. 설계시 제약조건은 고유진동수와 부재응력, 변위제약조건들이 적용되었다. 유전자 알고리즘에는 번식과장에서 엘리트 개체가 2번 사용되도록 하였으며, 제약조건 위반시 패널티를 사용하는 방법을 사용하였다. We present optimum design for truss and frame structures subject to constraints on stresses, displacement, and natural frequency. The optimum design procedure is used discrete and continuous design variables and Genetic Algorithms. Genetic Algorithms is used the method of Elitism and penalty parameters in order to improved fitness in the reproduction process, and optimum design is used steel(W-section) and pre-made discrete cross-section. Truss and frame structures optimization examples are used for 10-Bar truss, 25-Bar truss, 1-bay 2-story frame, 1-bay 7-story frame, and these examples are employed to demonstrate the availability and serviceability of Genetic Algorithms for solving optimum design of truss and frame.

유전자 알고리즘을 이용한 뼈대구조물의 이산최적화

김봉익(BONG-IK KIM),권중현(JUNG-HYUN KWON) 한국해양공학회 2002 韓國海洋工學會誌 Vol.16 No.4

This paper is to find optimum design of plane framed structures with discrete variables. Global search algorithms for this problem are Genetic Algorithms(GAs), Simulated Annealing(SA) and Shuffled Complex Evolution(SCE), and hybrid methods (GAs-SA, GAs-SCE). GAs and SA are heuristic search algorithms and effective tools which is finding global solution for discrete optimization. In particular, GAs is known as the search method to find global optimum or near global optimum. In this paper, reinforced concrete plane frames with rectangular section and steel plane frames with W-sections are used for the design of discrete optimization. These structures are designed for stress constraints. The robust and effectiveness of Genetic Algorithms are demonstrated through several examples.

하모니 서치 알고리즘과 고유진동수 제약조건에 의한 트러스의 단면과 형상 최적설계

김봉익(Bong-Ik Kim),권중현(Jung-Hyun Kwon) 한국해양공학회 2013 韓國海洋工學會誌 Vol.27 No.5

We present the optimum design for the cross-sectional(sizing) and shape optimization of truss structures natural frequency constraints. The optimum design method used in this paper employs continuous design variables and the Harmony Search Algorithm(HSA). HSA is a meta-heuristic search method for global optimization problems. In this paper, HSA uses the method of random number selection in an update process, along with penalty parameters, to construct the initial harmony memory in order to improve the fitness in the initial and update processes. In examples, 10-bar and 72-bar trusses are optimized for sizing and 37-bar bridge type truss and 52-bar(like dome) for sizing and shape. Four typical truss optimization examples are employed to demonstrate the availability of HSA for finding the minimum weight optimum truss with multiple natural frequency constraints.

유전자 알고리즘을 이용한 철근콘크리트 보의 단면 최적설계

김봉익(Bong-Ik Kim),권중현(Jung-Hyun Kwon) 한국해양공학회 2009 韓國海洋工學會誌 Vol.23 No.6

We present an optimum design method jar a rectangular reinforced concrete beam using Genetic Algorithms. The optimum design procedure in this paper employs 2 design cases: ⅰ) all of the design variables (b, d, As) of the rectangular reinforced concrete section are used pseudo-continuously, ⅱ) one is pseudo-continuous for the concrete cross section (b, d) and the other is discrete, using an index jar the steel area (As). The optimum design in this paper uses Chakrabarty's model. In this paper, the Genetic Algorithms use the method of Elitism and penalty parameters to improve the fitness in the reproduction process, which leads to very practical designs. The optimum design of the steel area in the examples uses ASTM standard reinforcing bars (#3#~11, #14, #18).

유전자 알고리즘을 이용한 트러스의 최적설계

김봉익(BONG-IK KIM),권중현(JUNG-HYUN KWON) 한국해양공학회 2003 韓國海洋工學會誌 Vol.17 No.6

Optimum design of most structural systems requires that design variables are regarded as discrete quantities. This paper presents the use of Genetic Algorithms for determining the optimum design for truss with discrete variables. Genetic Algorithms are known as heuristic search algorithms, and are effective global search methods for discrete optimization. In this paper, Elitism and the method of conferring penalty parameters in the design variables, in order to achieve improved fitness in the reproduction process, is used in the Genetic Algorithm. A 10-Bar plane truss and a 25-Bar space truss are used for discrete optimization. These structures are designed for stress and displacement constraints, but buckling is not considered. In particular, we obtain continuous solution using Genetic Algorithms for a 10-bar truss, compared with other results. The effectiveness of Genetic Algorithms for global optimization is demonstrated through two truss examples.

고유진동수 제약조건을 고려한 프레임 구조물의 최적화

김봉익(Bong-Ik Kim),이성대(Seong-Dae Lee) 한국해양공학회 2010 韓國海洋工學會誌 Vol.24 No.6

We present the minimum weight optimum design of cross sectional for frame structures subject to natural frequency. The optimum design in this paper employ discrete and continuous design variables and Genetic Algorithms. In this paper, Genetic Algorithms is used in optimization process, and be used the method of Elitism and penalty parameters in order to improved fitness in the reproduction process. For 1-Bay 2-Story frame structure, in examples, continuous and discrete design variables are used, and W-section (No.1~No.64), from AISC, discrete data are used in discrete optimization. In this case, Exhaustive search are used for finding global optimum Continuous variables are used for 1-Bay 7-Story frame structure. Two typical frame structure optimization examples are employed to demonstrate the availability of Genetic Algorithms for solving minimum weight optimum of frame structures with fundamental and multi frequency.

플라이애시 수중불분리성 콘크리트의 수밀성에 관한 실험적 연구

권중현(JUNG-HYUN KWON),김봉익(BONG-IK KIM) 한국해양공학회 2008 韓國海洋工學會誌 Vol.22 No.4

This paper describes the effects of fly ash replacement on the water tightness of antiwashout underwater concrete, which replaced the cement with fly ash from 0% to 30%. The experimental work was performed to find out the depth of permeation of concrete specimens cast in air and cured in 23℃ tap water using an open center pressure type of water permeation tester. The results showed that the permeation depth values of antiwashout underwater concrete were deeper than normal concrete, but that an admixture using fly ash during antiwashout underwater concrete casting in air made it more watertight than normal concrete according to the water permeation testing. SEM observations of the specimensof fly ash antiwashout underwater concrete showed that it wasmore packed with structures because of the pozzolan reaction of the fly ash and cement.

플라이애시를 혼입한 수중불분리성 콘크리트의 내 황산염에 관한 실험적 연구

권중현(Joong-Hyen Kwon),김봉익(Bong-Ik Kim) 한국해양공학회 2011 韓國海洋工學會誌 Vol.25 No.3

This paper describes the effects of fly ash replacement on the sulfate resistance of antiwashout underwater concrete which was replaced cement by fly ash from 0% to 50%. and the experimental works were performed on sulfate acceleration test of 5%Na₂SO₄ solution to find out the variance of length and weight if specimens. The experimental result shows that the length if specimens of antiwashout underwater concrete age at 180day was highly increased compare with normal concrete by acceleration test. but the mixture which was replaced 50% of fly ash shows reduction if the expansion, weight various, compare with normal concrete specimen. accordingly by using fly ash as admixture in antiwashout underwater concrete in sea environment, it will makes more durable for the attacks of sulfate by sea water.

플라이애쉬를 사용한 수중불분리성 콘크리트의 응결에 관한 실험적 연구

권중현(JUNG-HYUN KWON),김봉익(BONG-IK KIM) 한국해양공학회 2001 韓國海洋工學會誌 Vol.15 No.4

This paper describes the effect of fly ash replacement on the setting time of antiwashout underwater concrete, where cement was replaced by 0% to 50%. Experimental work was performed on the condition of sea water and in air to find out the characteristics of setting time between the concretes that were cast in air and cast in 15℃ of sea water. The experimental results show that the setting time of underwater concrete with 50% replacement was delayed about 10 hours than normal concrete. And it can be concluded that, at the case of underseawater concrete addicted with fly ash the delayed final setting times are shown as the function Tf=0.069F+7.69, where Tf is the delayed final setting time and F is quantity of fly ash respectively. These results confirm that the setting time of underseawater concrete could be prolonged.