一种带区间变量混合模型的结构可靠性分析方法

摘要

工程结构分析和设计中存在着诸多不确定量,部分不确定量因信息量有限很难精确得到概率分布函数,只能给定变化区间.本文中在全概率模型可靠性分析的基础上引入区间变量,针对既有随机变量又有区间变量的混合模型,提出一种新的可靠性分析方法.它先利用优化方法找出原空间内概率密度最大的点,再结合一次渐近积分法,求解出混合模型的最大失效概率.最后通过两个数值算例和一个工程应用验证了该方法的有效性.%Uncertain variables widely exist in engineering structural analysis and design. Due to limited information , some of them are difficult to get their probability density function precisely, and only their varying intervals can be given. In this paper, interval variables are introduced on the base of reliability analysis on full probability model, and a new method of reliability analysis is proposed for hybrid model with both random variables and interval variables. With the method the point with maximum probability density in original space is located and the maximum probability of failure in hybrid model is then calculated with first-order asymptotic integration. In the end the effectiveness of the method is verified with two numerical examples and an engineering application.