多种不确定性并存情形下的非常规可靠性度量方法

Study of Unconventional Reliability Measure Methods in the Case of Several Uncertainties Coexisting

多种不确定性(如随机性、模糊性和不完全可信性)并存的情形在现实中很常见,但此情形下的可靠性度量并未得到充分研究。本文基于模糊理论和云理论提出了一种适用于上述情形的可靠性度量方法,即:首先针对应力、强度中的模糊变量,根据其不完全可信性采用云理论对其隶属函数进行云化处理,并在不同可信度下获得以上、下隶属函数描述的正态云生成区间值Fuzzy集;然后对上、下隶属函数进行处理,使其拥有概率密度函数的数学特征,进而采用常规的应力-强度干涉模型计算可靠度的上、下限,构造一个可靠度区间,最终获得一条由一系列可靠度区间及其相应的可信度构造的分布曲线,以此作为可靠性度量结果。本文方法不仅可综合处理多种不确定性,且能使更多信息保留在可靠性度量结果中。

A variety of uncertainties including randomness, fuzziness and incomplete credibility coexist in reality. Even though this situation is common, it is not fully researched. An unconventional method is proposed which can deal with above-mentioned uncertainties. This method is based on fuzzy theory and cloud theory. First, make the incomplete credibility information of fuzzy stress and intensity variables cloudization by using the theory of cloud. And get the Gaussian cloud formed interval-valued Fuzzy sets which are described by the upper and lower membership functions at different credibility. Then, deal with upper and lower membership functions to make them have the mathematical characteristics of probability density function. In this way, the upper and lower limit values can be calculated with conventional stress-intensity interference model and a reliability interval can be constructed. At last, the reliability measure results curve which consists of a series of reliability intervals and their corresponding credibility can be obtained. The method not only can deal with a variety of uncertainties comprehensively, but also can keep more information in reliability measure results.