以可靠性为约束的结构优化

 常规结构优化设计存在以下两个根本缺陷:首先,没有确切考虑载荷及元件强度实际存在的不确定性,而用安全系数给以笼统的概括。安全系数取值一般较大,元、对结构带来的影响往往比经过优化设计所得到的效益还要大。第二,它是用元件的应力约束来保证结构系统安全,因此,它是结构元件安全基础上的优化设计。从系统论的观点看,元部件功能好整体功能不一定好。

STRUCTURAL OPTIMIZATION WITH CONSTRAINT OF STRUCTURAL SYSTEM RELIABILITY

In this paper the problem of optimized structure design with the constraint of structure system reliability is investigated. In the reliability analysis of structure systems, the incremental load approach proposed by Fred Moses is applied to multi- loading situations. In the optimized design, a large step search method based on the concept of gradient projection is proposed. The method fully takes the advantages of the large step search method and the interpolating method and overcomes the defect of large step search method, i.e., its convergence rate is rather slow a't the end of each iteration. Several examples are computed.The results show that this method can really increase the convergence rate remarkably.