Reliability Analysis Of Standby Redundant Systems With Uncertain Lifetimes

With the intensification of competition in the areas of industrial production,aerospace,and engineering control,manufacturers are increasingly pursuing high reliability of their equipments,and in particular,the certain key components or subsystems of the system are often required to use redundant configurations.Because of the imprecise information in the operation of the system,which include objective uncertainty,subjective uncertainty,and dual uncertainty.Therefore,in this paper,the researches on the standby redundant systemwith different structures and different environment are as follows:Firstly,the reliability of unrepairable warm standby system with fuzzy parameters is studied.That is,the lifetimes and warm standby times of components are assumed to have random fuzzy exponential distributions,then the mathematical models of warm standby systems consisting of two dissimilar components are established and the reliability analysis is carried out.Moreover,the expressions of reliability and mean time to failure are presented for each unrepairable warm standby system,respectively.If the fuzzy parameters degenerate to constants,the results are consistent with the results in stochastic case.In addition,when there is no sufficient sample data in the system reliability analysis,the domain experts are invited to evaluate the belief degree that each event will happen.Therefore,uncertain variables are introduced to describe the unrepairable cold standby systems and repairable systems of several specific structures.The study is about reliability analysis of unrepairable cold standby systems based on uncertainty lifetimes.The lifetimes of components in the cold standby systems are assumed to be independent and nonnegative uncertainty variables in this paper.The basic mathematical models of three unrepairable cold standby systems are considered,namely,unrepairable cold standby systems with absolutely reliable conversion switches,unrepairable cold standby systems with 0-1 mode conversion switches and unrepairable cold standby systems with continuous mode conversion switches.The expressions of reliability and mean time to failure of the three cold standby systems are arrived,respectively.Finally,the lifetimes and repair times of components of typical repairable systems are assumed to be mutually independent uncertain variables.Based on the above assumptions,we establish the uncertain reliability mathematical models of repairable series systems,parallel systems,series-parallel systems and parallel-series systems.The reliability characteristics in the uncertainty context are studied.The systems are described by steady state availability,steady state failure frequency,mean up time and mean down time.Then some numerical examples are given.When the fault data is insufficient,the reliability modeling and evaluation method have a stronger model description ability,which makes the system reliability evaluation more effective and reasonable,and makes the reliability assessment closer to the engineering practice.The papers studied the reliability of standby redundant systems from a new viewpoint.The random fuzzy theory and uncertainty theory are applied to the research of reliability of standby redundant systems,respectively.At the same time,the research also provides new ideas,new methods and new technologies for the development of reliability mathematics,computer science and other related fields.It not only has great academic significance,but also has important practical value and wide application.