Reliability analysis of a cold-standby system considering the development stages and accumulations of failure mechanisms

Abstract

In this paper we classify failure mechanisms (FMs) into three types based on the triggering loads, including environmental load-triggered (E-type), operating load-triggered (O-type), and combined load-triggered (C-type) FMs. In a cold-standby component, E-type FMs develop when the component does not operate and may develop with different speeds due to changes in the environmental conditions at different stages. O-type FMs are triggered by operational loads. Environmental loads and operating loads are necessary for triggering C-type FMs. Previous studies have often assumed that cold-standby components are not subject to failures or degradation in the standby stage. However, E-type FMs can develop in cold-standby components at the standby stage and contribute to the degradation of the components. In this paper, we propose a hierarchical method based on the sequential binary decision diagram (SBDD) to analyze the reliability of a non-repairable cold-standby system while considering the correlation and development of FMs. In the case study, a reliability analysis is conducted for an example power supply subsystem equipped with an electronic control device, which comprises one primary unit and one cold-standby unit. The results show that the reliability of the cold-standby system is quite different when considering the development of E-type FMs in the cold-standby unit. In addition, the lifetime of the system will decrease when E-type FMs are considered in the simulation.