| According to the RAMS(Reliability,Availability,Maintainability,and Safety)architecture,the system reliability and maintainability are guarantees for system safety and availability,and there is an interaction between availability and safety of the system.However,currently,basic research data on the reliability of most metro signal equipment is mainly used for theoretical predictions,while the reliability of data has not been validated by actual operation data.The formulation of signal system maintenance strategies mainly relies on experience,thus,improper equipment maintenance methods and timing,and unscientific allocation of equipment maintenance resources could result in high equipment failure rates and maintenance costs,affecting the safety and availability indicators of the signal system in operation.How to use the RAMS-based system to study the metro signal system under the premise of satisfying certain safety and availability,reduce the failure rate,and save the maintenance cost of the signal system,is an engineering management problem related to the sustainable development of metro in China.Based on the RAMS system specifications,this thesis constructs the RAMS evaluation system for the metro system.The Weibull distribution has been used to predict the reliability of signal equipment,and the reliability analytical model has been built to calculate the sensitivity of signal system reliability index,and then a dynamic evaluation model of signal system safety risk has been built.Moreover,a signal system maintenance strategy has been proposed,which comprehensively considers the equipment comprehensive criticality and system average reliability and maintenance cost to get an optimal performance under the set of safety risk threshold and availability conditions.A comprehensive maintenance and management platform forsignal system operation is developed.The specific research contents are as follows:(1)Based on the study of the RAMS system specifications,the evaluation system of the RAMS of the metro signal system has been established.According to related industry standards and specifications,evaluation criteria of the RAMS of the metro signal system has been defined,and the safety risk assessment system of the metro signal system has been constructed,also,reliability analysis model of the metro signal system is proposed based on state vector data and probability theory.(2)The boundary conditions of safety(S)and availability(A)have been explored,and the time-varying law of the reliability(R)prediction of signal system equipment and safety risk evaluation of the signal system has also been studied.The Weibull distribution has been used to analyze the distribution law of signal system equipment reliability.Also,the reliability analytical model has been built to calculate the sensitivity of signal system reliability index to related parameters.And a dynamic evaluation model and analysis method of signal system safety riskhas been proposed based on the reliability prediction of the signal equipment.(3)Interactions among safety(S),availability(A),reliability(R),and maintenance cost has been analyzed,and the maintenance strategy of the signal system has been investigated.According to the impact of equipment failure on system safety,availability,maintainability and economy,the comprehensive criticality of equipment has been defined,based on which an equipment maintenance classification method has been proposed.Taking the threshold of dynamic safety risk evaluation of the signal system and set system availability as constraints,to construct a multi-objective function regarding the equipment average reliability and maintenance cost,and obtains Pareto solution set by using a multi-objective optimization algorithm.Based on the analysis and research above,a signal system maintenance strategy has been proposed based on the combination of comprehensive criticality of equipment and multi-objective optimization algorithm set.(4)On the basis of the above theory and research,an integrated maintenance management platform of signal system operation has been developed,which provides functionalities such as equipment state monitoring,safety risk dynamic analysis of the signal system and equipment maintenance program push.The platform has been applied in metro operations in Shenzhen,Kunming,Nanning and so on.The practice has proved that the use of the platform reduced the failure rate and the maintenance cost of the signal system,improved the maintainability,ensured the system safety and availability,and verified the scientificness and rationality of theoretical research in the paper.The research can be potentially applied to the maintenance and management of other metro systems. |
