Reliability Equivalence Factors for Coherent System using Survival Signature

Abstract

This study presents a methodology aimed at enhancing the performance of coherent systems through the application of survival signature analysis, focusing on the calculation of reliability equivalence factors (REFs). In the context of system improvement, the selection of reliability improvement strategies, such as reduction and duplication, depends on various factors like space limitations, costs, and other constraints. The importance of REF lies in their ability to quantify the extent of reliability improvement, providing a clear metric for decision-makers to assess the cost-effectiveness of various enhancement strategies. The analysis focuses on two distinct types of REFs, namely, mean reliability equivalence factors (MREFs) and survival reliability equivalence factors (SREFs), targeted at reliability enhancement via strategies including component failure rate reduction and the implementation of warm standby duplication. Both perfect and imperfect switching scenarios in warm duplication are examined, with survival signature analysis applied to determine the system's survival function and mean time to failure (MTTF). The methodology's effectiveness is illustrated through a case study of a six-unit bridge system, where the components are modeled using exponential and Weibull distributions. REFs are evaluated for sequential upgrades in either individual components or entire component types. The study also conducts a comparative analysis between the reliability and MTTF of the original and improved systems across different improvement techniques.