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Research Paper

Structural Design Optimization of Lightweight Offshore Helidecks Using a Genetic Algorithm and AISC Standard Sections

유전 알고리듬 및 AISC 표준 단면을 사용한 경량화 헬리데크 구조 최적설계

Kichan Sim1
,
Byungmo Kim2
,
Chanyeong Kim1
,
Seung-Hyun Ha3†
심 기 찬1
,
김 병 모2
,
김 찬 영1
,
하 승 현3†
1Graduate Student, Department of Ocean Engineering, Korea Maritime and Ocean University, Busan, 49112, Korea
2Graduate Student, Department of Convergence Study on the Ocean Science and Technology, Korea Maritime and Ocean University, Busan, 49112, Korea
3Associate Professor, Department of Ocean Engineering, Korea Maritime and Ocean University, Busan, 49112, Korea
1한국해양대학교 해양공학과 석사과정
2한국해양대학교 해양과학기술융합학과 박사과정
3한국해양대학교 해양공학과 부교수
†Corresponding author: Tel: +82-51-410-5246; E-mail: shha@kmou.ac.kr
31 December 2019. pp. 383-390
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Abstract

A helideck is one of the essential structures in offshore platforms for the transportation of goods and operating personnel between land and offshore sites. As such, it should be carefully designed and installed for the safety of the offshore platform. In this study, a structural design optimization method for a lightweight offshore helideck is developed based on a genetic algorithm and an attainable design set concept. A helideck consists of several types of structural members such as plates, girders, stiffeners, trusses, and support elements, and the dimensions of these members are typically pre-defined by manufacturers. Therefore, design sets are defined by collecting the standard section data for these members from the American Institute of Steel Construction (AISC), and integer section labels are assigned as design variables in the genetic algorithm. The objective is to minimize the total weight of the offshore helideck while satisfying the maximum allowable stress criterion under various loading conditions including self-weight, wind direction, landing position, and landing condition. In addition, the unity check process is also utilized for additional verification of structural safety against buckling failure of the helideck.

Keywords
offshore helideck
AISC standard sections
genetic algorithm
unity check
safety evaluation

본 논문에서는 AISC 표준 단면을 설계 변수로 하는 캔틸레버 타입 헬리데크 모델의 유전 알고리즘 최적설계를 소개한다. AISC 표준 단면을 단면 형상별로 분류하고 단면적 순으로 정렬한 후 정수 단면 번호를 부여하여 설계 변수로 최적설계를 수행하였다. 이 과정을 통하여 이산화된 설계 변수를 가지는 최적설계 문제를 해결하기 위해 유전 알고리즘을 적용하였다. 또한, 제약조건으로 허용응력 및 허용응력비 검사 조건을 모두 고려하여 구조물의 구조 안정성을 고려한 설계를 수행하였다. 최적설계 과정중 매 반복계산 마다 수행되는 구조해석 시간을 단축시키기 위해 선형 중첩법을 사용하였고, 이를 통해 구조 해석 시간을 약 75% 감소시킬 수 있었다. 또한 헬리데크 최적설계의 경량 효과를 높이기 위해 부재 그룹 세분화를 하였고, 그 결과를 선행 연구 모델, 기존의 부재 그룹 모델과 비교하였다. 그 결과 선행연구 대비 약 30톤의 부재를 절감할 수 있었 으며, 구조적으로도 보다 안전한 헬리데크 설계를 얻을 수 있었다.

키워드
헬리데크
AISC 표준 단면
유전 알고리즘
허용응력비 검사
구조 안전성 평가
References
1
American Institute of Steel Construction (AISC) Inc. (1989) Allowable Stress Design and Plastic Design, 9th edition.
2
American Institute of Steel Construction (AISC) Inc. (2017) AISC Shapes Database v15.0, AISC Steel Construction Manual, 15th edition.
3
American Pertroleum Institute (API) (1996) Recommended Practice for Planning Designing, and Constructing Heliports for Fixed Offshore Platforms, 4th edition.
4
ANSYS Inc. (2017) ANSYS Mechanical APDL Command Reference, Release 18.2.
5
Balling, R.J., Briggs, R.R., Gilman, K. (2006) Multiple Optimum Size/Shape/Topology Designs for Skeletal Structures Using a Genetic Algorithm, J. Struct. Eng., 132(7), pp.1158~1165. 10.1061/(ASCE)0733-9445(2006)132:7(1158)
10.1061/(ASCE)0733-9445(2006)132:7(1158)
6
Civil Aviation Authority (CAA) (2013) Standards for Offshore Helicopter Landing Areas, CAP-437.
7
Deb, K., Gulati, S. (2001) Design of Truss-structures for Minimum Weight Using Genetic Algorithms, Finite Elem. Anal. &Des., 37(5), pp.447~465. 10.1016/S0168-874X(00)00057-3
10.1016/S0168-874X(00)00057-3
8
Det Norske Veritas (DNV) (2001) Helicopter Decks, DNV-OS-E401.
9
Holland, J.H. (1975) Adaptation in Natural and Artificial Systems, The MIT Press, Cambridge, pp.217.
10
International Civil Aviation Organization (ICAO) (1995) Heliport Manual, 3rd edition. Doc9261- AN/903.
11
Jung, T.-W., Kim, B.-M., Ha, S.-H. (2017) A Study on Lightweight Design of Cantilever-type Helideck Using Topology Optimization, J. Comput. Struct. Eng. Inst. Korea, 30(5), pp.453~460. 10.7734/COSEIK.2017.30.5.453
10.7734/COSEIK.2017.30.5.453
12
Kim, B.-M., Leem, J.-J., Ha, S.-H. (2018) Safety Evaluation of a Cantilever-type Helideck under Nonlinear Buckling, J. Korean Soc. Mar. Eng., 42(3), pp.203~209. 10.5916/jkosme.2018.42.3.203
10.5916/jkosme.2018.42.3.203
13
Mathworks Inc. (2004) Genetic Algorithm and Direct Search Toolbox for Use with Matlab, p.222.
14
Rahami, H., Kaveh, A., Gholipour, Y. (2008) Sizing, Geometry and Topology Optimization of Trusses via Force Method and Genetic Algorithm, Eng. Struct., 30(9), pp.2360~2369. 10.1016/j.engstruct.2008.01.012
10.1016/j.engstruct.2008.01.012
Information
  • Publisher :Computational Structural Engineering Institute of Korea
  • Publisher(Ko) :한국전산구조공학회
  • Journal Title :Journal of the Computational Structural Engineering Institute of Korea
  • Journal Title(Ko) :한국전산구조공학회 논문집
  • Volume : 32
  • No :6
  • Pages :383-390
  • Received Date : 2019-09-20
  • Revised Date : 2019-09-27
  • Accepted Date : 2019-09-28
  • DOI :https://doi.org/10.7734/COSEIK.2019.32.6.383
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