基于灵敏度的可靠性优化解耦方法

针对航空结构可靠性优化设计问题,提出了一种基于灵敏度的可靠性优化(RBO)解耦方法。首先将高效求解的可靠性灵敏度用于失效概率函数(FPF)的快速构建,其优点在于仅需要一次可靠性分析即可得到失效概率函数的局部近似,克服了常规求解方法中需要多次可靠性分析的缺点;然后将得出的FPF近似代入RBO模型中,将原问题解耦成确定性优化子问题,可用常规优化方法来求解。另外,采用了序列近似优化策略来保证可靠性优化解的正确性。文中给出了复合材料梁和机翼三盒段结构的优化求解算例来说明本文方法的可行性和正确性。

A decoupling method of reliability optimization based on sensitivity

A decoupling method based on reliability sensitivity is proposed for the reliability-based optimization (RBO) design of aeronautic structure. It utilizes reliability sensitivity to construct the explicit approximation of the failure probability function (FPF) with respect to design variables quickly, thus its advantage is that it only needs one reliability analysis and repeated reliability analyses can be avoided. After the approximation of the FPF is established, the target RBO problem can be transformed into a deterministic one which can be solved by conventional optimization strategies. Meanwhile, a sequential approximate optimization framework is adopted to guarantee the accuracy of the solution. Examples of composite beam and three-box simulated flap structure are given to demonstrate the feasibility and validity of the proposed optimization method.