抗冰海洋平台的全寿命优化设计Ⅱ—算法与应用

Life-cycle cost-effective optimum design of ice-resistant offshore platforms Ⅱ—algorithms and application

针对抗冰海洋平台全寿命优化设计模型中的不同类型可靠度分析问题,提出了相应的计算方法,包括冰区导管架平台整体抗力和极值冰力响应的概率统计特性及整体可靠度的高效近似算法,基于首次超越破坏机制的海洋平台冰振动力可靠性分析,基于等效应力幅值近似计算的疲劳寿命分析等。最后,以渤海某抗冰平台为例,实现了全寿命总费用最小的抗冰海洋平台优化设计。结果表明,基于风险的全寿命优化模型比基于规范的静力设计和仅考虑动力的最优设计相比更加合理。

Different algorithms corresponding to the evaluation of life-cycle cost are proposed,including the approximate static global reliability analysis based on the statistical properties of the global resistance and extreme responses,dynamic reliability analysis based on first passage breakage mechanism and fatigue life analysis based on the approximate explicit formula of nodes stress with respect to the ice velocity and thickness.An illustrative design example of a practical platform in Bohai Bay is optimized based on the above model and formulations, with the global stiffness as the design variable. The life-cycle optimum results are discussed and compared with the conventional static design （the real design） and the dynamic deterministic optimum design,which can be concluded that the life-cycle cost-effective optimum design model proposed in this paper will lead to a more rational, economical and safer design.