复杂多态系统的区间值模糊贝叶斯网络建模与分析

Reliability modeling and analysis of complex multi-state system based on interval fuzzy Bayesian network

随着现代工程系统结构复杂度的增加以及运行环境的复杂化,传统的可靠性分析与评估技术已不能满足现代工程系统需求.针对复杂多态系统可靠性分析与评估的需求,本文从部件状态分析、系统结构分析入手,对存在认知不确定性同时考虑失效相关性的复杂多态系统进行可靠性建模与分析.由于现代复杂多态系统信息输入及系统故障影响因素的多样性,以及系统冗余,使得不确定性和共因失效对复杂多态系统可靠性分析和评估至关重要.本文借助贝叶斯网络对多态系统的图形表达和推理优势,采用模糊理论中区间值三角模糊数对部件概率进行描述;同时利用β因子模型对共因失效进行量化,再将其以新增共因节点的方式实现共因失效的贝叶斯网络建模,从而提出基于区间值模糊贝叶斯网络的复杂多态系统可靠性分析方法.最后,将基于区间值模糊多态贝叶斯网络对具有共因失效的多态卫星天线双轴定位机构传动系统进行可靠性分析.通过对实际工程系统的分析,表明本文建立的多种因素影响下复杂多态系统的可靠性建模和分析方法,进一步完善了复杂系统可靠性分析理论与方法.

With the increasing complexity and large size of modern advanced engineering systems, the traditional reliability analysis and evaluation technology which is based on large number of sample data cannot meet the demand of complex system.Aiming at the engineering application requirement, this paper focuses on the reliability modeling and analysis of complex system with uncertainties and failure dependencies. Due to the diversity of input information and the system failure factors,and system redundancies, the uncertainty and common cause failure（CCF） have become the most important factors for reliability analysis and evaluation of complex system. In consideration of the epistemic uncertainty caused by lack of probability statistical information, the fuzzy theory is employed to express the fuzzy information of system, and the basic events failure probabilities are described by interval-valued fuzzy numbers. Taking account of the influence of CCF to system reliability and the widespread presence of MSS in engineering practices, the CCF is quantified by the β factor parameter model and integrated to Bayesian Network（BN） model through a new defined common cause node. Finally,a comprehensive method for reliability modeling and assessment of a multi-state system（MSS） with CCFs based on interval-valued fuzzy BN is proposed by taking the advantage of graphic representation and uncertainty reasoning of BN.The method has applied to the transmission system of two-axis positioning mechanism of a satellite antenna to demonstrate its effectiveness and capability for directly calculating the system reliability on the basis of multi-state probabilities of components. It has shown that the method proposed has done further improvement of the theory for reliability analysis of complex system and can realize its engineering application.