基于可靠性约束的结构优化设计技术研究

建立结构重量最小化、可靠度为约束的优化模型。将结构近似为串联可靠度模型，每个元件作为一失效单元；由应力状况建立元件的失效函数。采用一次二阶矩法求解元件的可靠性指标；用元件失效概率的和来表示结构失效概率；将结构失效概率的允许值平分给元件，建立设计变量的显示迭代式，并用满可靠度法进行修正，获得最终设计结果。在开展结构静强度优化设计的同时，对元件在线弹性范围内的屈曲可靠性优化设计问题做了初步的研究。桁架结构和机翼盒段结构的可靠性优化结果表明，与现有方法相比，本文提出的方法在具有较高精度的同时，极大地提高了优化设计的效率。

Technology study on reliability-based structural optimization and design

Firstly, the structure was treated as a serial reliability model, in which every component became a failed unit, so that the trivial searching main failure modes of the structure was avoided. Secondly, the reliability index of each component was computed with a method called first order second moment, then in order to simplify the ascertain procedure of the structural failure probability, it was equal to the sum of components failure probability. Finally, the allowable value of structural failure probability was evenly allocated to every component, and a criterion method was used to construct a formula for searching the optimal solution. Besides static strength, the problem of optimization and design was studied when the failure took place owing to structural linear elastic buckling in this paper also. Several structural examples including truss and wing box were employed to validate the proposed method. Compared with present methods, the results indicate that the proposed method greatly increases the efficiency and has appropriate accuracy.