Structural Design Optimization of Offshore Helidecks Based on Genetic Algorithm with AISC Standard Sections

A helideck is one of essential structures in the offshore platform for the transportation of goods and operating personnel between land and offshore sites, and it should be carefully designed and installed for the safety of the offshore platform. In this study, the structural design optimization method for the lightweight offshore helideck is developed based on genetic algorithm and attainable design set concept. A helideck consists of several types of structural members such as plate, girder, stiffener, truss and support elements, and the dimensions of these members used to be pre-defined by the manufacturers. Therefore, we defined the attainable design sets by collecting all the standard section data for these members from American Institute of Steel Construction (AISC), and assigned the integer section labels as the design variables in the genetic algorithm process. The objective is to minimize the total mass of the offshore helideck while satisfying maximum allowable stress criterion under various loading conditions including self-weight, wind directions, landing positions, and landing conditions. In addition, the unity check process is also applied for the additional verification of structural safety from the buckling failure of the helideck.1. 서 론 1 2. 헬리데크 모델링 및 설계하중 산정 3 2.1 헬리데크의 기본구조 3 2.2 헬리데크 설계하중 산정 5 3. 헬리데크 최적설계 10 3.1 AISC 표준 단면 10 3.2 유전 알고리듬 16 3.3 허용응력 조건 21 3.4 허용응력비 검사 조건 23 3.5 선형 중첩법 25 3.6 헬리데크 최적설계 정식화 28 4. 헬리데크 최적설계 결과 31 4.1 부재 그룹 4개 모델 32 4.2 부재 그룹 10개 모델 41 5. 결론 49 참고문헌 51Maste