基于梁板结构的船舶系统可靠性分析及其优化

System Reliability Analysis and Optimization for Vessels Based on Girder-plate Structure

采用梁元和加筋板格元来模拟船舶空间结构,并建立相应的系统可靠性分析与优化模型。针对加筋板格可靠性分析中计算反向结点力向量时忽略加强筋影响而导致计算结果偏于保守的缺点,采用了完整加筋板格元的反向结点力向量和修正刚度矩阵,在此基础上采用分支限界法搜索系统主要失效模式并对其提出改进措施,保证了计算精度并提高了计算效率;运用界限搜索法求解模糊约束集的最优水平截集,进而求得系统可靠性约束下结构质量的模糊最优解,并与确定性优化设计结果对比,结果显示模糊优化模型具有更好的经济效益,可供工程借鉴使用。

The system reliability and optimization model for vessels was established by adopting hybrid girder element and stiffened plate （SP） element. The opposite vector of equivalent nodal force and modified stiffness matrix were utilized to ensure calculation accuracy in the reliability analysis of stiffened sheet panel. The significant failure modes were identified by using the improved branch-and-bound method. The optimum level cutest which is the intersection of fuzzy constraint sets was determined with bound search method, and the fuzzy optimum solutions were finally obtained. The results were compared with those of deterministic optimization methods, which shows that the fuzzy optimization model is more effective and can be used in engineering design.