A Survival Signature Framework for Reliability and Component Importance Analysis of Coherent Systems with Cold Standby Components

Abstract

This study focuses on evaluating the system’s reliability and identifying component criticality for a coherent system through the survival signature method. The Relative Importance Index is employed to identify critical components in the main system configuration before redundancy implementation. To enhance system reliability, each component is transformed into a subsystem containing active and independent non-identical standby components, where the standby components are analyzed both with and without degradation. Convolution-based recursive expressions are employed to evaluate the subsystem’s reliability. Thereafter, system reliability and component importance measures are evaluated using the survival signature method for both the main system and the redundant system. A numerical illustration demonstrates that introducing cold standby redundancy, with and without degradation, significantly improves system reliability. It is also found that, even though the highly critical component of the original system remains influential, the relative criticality of subsystems under standby configurations changes over time, resulting in a shift in importance ranking. This redistribution of criticality highlights the effectiveness of the proposed redundancy strategy in improving system performance.