结构系统可靠度约束下的一种结构优化方法

以结构系统的可靠度作为结构优化设计的控制参数。文中的元件内力由有限元法求得，并由计算机自动形成失效模式的安全余量方程；用分枝限界法判认主要失效模式；用ＰＮＥＴ法计算结构系统的可靠度；导出了结构系统可靠度的敏度分析表达式，使高效率进行基于结构可靠性的优化设计成为可能。采用基于约束函数－阶泰劳展开的序列近似规划及非线性规划的对偶理论，导出了求解结构系统可靠度为约束的最小重量设计问题的优化迭代公式。若干例题的计算结果表明，本文提出的方法是相当有效的①。

A Structural Optimization Method with Reliability Constraints of Structural System

n this paper, the reliability of structural system is the governing parameter for the Structural optimization design. The paper gives the internal force of members of trass structures by using the finite element method of structural analysis. The safety margin of the failure modes is generated automatically by computer. The significant failure modes are identified by using the branch-and-bound method. The reliability of the structural system is evaluted by PNET method. The expression of sensitivity analysis for the structural sys-tem reliability is derived, thus making the optimal reliability-based design be carried on with high efficiency is possible. The optimum design problem with the constraint of the Structural system reliability is solved by using the sequential approximate programming thchnique based on the first order Taylor series expansion of constraint function and dual theory of nonlinear programming method. Several examples are evaluated. The results demonstrate that the method presented in the paper is quite effective.