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

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.