Reliability Engineering and Services

2Reliability Estimation with Uncertainty

2.1 Introduction

This chapter introduces the reliability block diagram and presents reliability estimation methods for a variety of system structures, including series, parallel, mixed series‐and‐parallel, k‐out‐of‐n redundancy, and networks. The focus is on modeling and analysis of the uncertainty of component reliability estimates and its impact on the system reliability performance. Particularly, we propose block decomposition methods to calculate the variance of a system reliability estimate based on the moments of a component reliability estimate. Reducing reliability estimation uncertainty is of importance in terms of designing and operating risk‐averse systems in private and public sectors, including manufacturing, healthcare, transportation, energy, supply chains, and defense industries, where failures often lead to costly downtime or even human casualty. System reliability confidence intervals (CIs) are further derived under binomial, normal, and lognormal distributions. We also extend the binary reliability models to multistate systems. This chapter is concluded with the discussion of reliability importance measures.

2.2 Reliability Block Diagram

A reliability block diagram (RBD) is a graphical representation to capture the functional or operational interdependency of different components in a system. Each block represents a component or subsystem that possesses its own failure rate or reliability feature. For instance, if ...