冰区海洋平台整体可靠度分析高效近似算法

冰荷载是冰区海洋平台设计的控制荷载,极值冰力直接危害着平台结构整体的安全.以渤海辽东湾 JZ20-2 MSW、JZ20-2 NW 导管架海洋平台为例,考虑了冰荷载、构件几何尺寸、材料弹性模量、屈服强度、恒荷载的随机性,利用Monte-Carlo法进行随机抽样分析,得到了冰区导管架海洋平台结构整体抗力及极值冰力响应(顶点位移)的概率统计.在此基础上,提出了冰区海洋平台整体可靠度分析的高效近似算法,把功能函数简化为线性的显武表达式.数值算例表明该算法大大提高了计算效率,并具有满意的精度与适用性.

An efficient approximate method of global reliability analysis for offshore platforms in ice zone

Ice load is the dominative load in the design of offshore platforms in the ice zone, and the extreme ice load is the key factor that affects the safety of the platforms. Firstly, the statistical properties of the global resistance and extreme responses of the JZ20-2 MSW, JZ20-2 NW jacket platforms in Bohai Bay are studied using random sampling analysis by Monte-Carlo method, considering the randomness of ice load, dead load, steel elastic modulus, yield strength and structural member dimensions. Then, based on the above conclusions, an efficient approximate method of the global reliability analysis for the offshore platforms is provided, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. Finally, numerical examples of offshore jacket platforms in Bohai Bay demonstrate the satisfactory efficiency, accuracy and applicability of the proposed method.