Hazard recognition and reliability analysis of CTCS-3 on-board subsystem

Abstract

This paper presents an investigation of hazard sources identification and reliability sensitivity analysis of CTCS-3 on-board subsystem. Traditional quantitative and qualitative safety and reliability analysis generally used static analysis methods, such as Fault Tree. When device redundancy, dynamic logic and dynamic mechanism are taken into consideration, dynamic analysis methods are preferred, such as Dynamic Fault Tree (DFT). In this paper, the methods of Hazards and Operability (HAZOP), DFT and Monte Carlo Simulation (MCS) are used for quantitative and qualitative analysis. Firstly, to reflect the structure and functions of on-board subsystem, two models (i.e reference model and function hierarchical model) are built. HAZOP is applied to identify hazard sources of on-board subsystem according to above models. Secondly, DFT is put forward within which the top event is CTCS-3 on-board subsystem failure event and the basic events are from results of HAZOP analysis. Then, both MCS and Maximum Likelihood Estimation (MLE) are adopted to estimate the reliability parameters of the CTCS-3 on-board subsystem and components. Reliability sensitivity analysis is observing the variations in components’ reliability parameter contributing to the changes of Mean Time to Failure (MTTF) of CTCS-3 on-board subsystem. Finally, a failure density curve of CTCS-3 on-board subsystem and a table of MTTF sensitivity parameters are presented. According to the sensitivity table, it is knowledgeable for decision makers to take effective measures to improve the reliability of CTCS-3 on-board subsystem.