结构非概率可靠性优化设计

Non-probabilistic reliability optimization of structures

在结构质量限制条件下 ,提出了一个结构非概率可靠性优化设计的数学模型 .数学模型由两个优化过程组成 .第一个优化过程是在结构质量约束下极大化结构非概率可靠性 .第二个优化过程是在载荷不确定性条件下 ,考虑结构应力、位移约束和极小化结构质量 .其中第二个优化过程嵌套在第一个优化过程之中 .作为一个数字算例 ,用所提出的优化模型进行了一个桁架结构的非概率可靠性优化设计 .当关于所有不确定性载荷的信息严重缺乏时 ,设计者宜采用最小值最大化法则进行结构非概率可靠性优化设计 .设计者如果仅对某个不确定性载荷的特性知之甚少而对其他不确定性载荷的波动变化有较好的了解 。

In this paper, a mathematical model is proposed for the non probabilistic reliability optimization of structures. Two optimization procedures are employed in the proposed model. The first level optimization is to maximize the uncertainty parameter (non probabilistic reliability) under the condition of constraint of the structural weight. In consideration of stress and displacement constrains, the second one is to minimize the structural weight under the condition of uncertain loads, which is inserted into the process of the first optimization. The non probabilistic reliability optimization of a truss under uncertain loads is carried out based on the proposed model. The minimum maximum criterion is adopted on the condition that information on all uncertain loads is severely lack. If information on one uncertain load is severely lack only and others are available, the uncertainty parameter of that uncertain load is maximized while uncertainty parameters of other loads are determined based on available information.