CHAPTER 9 RELIABILITY ANALYSIS OF SYSTEMS by

Most systems are composed of several subsystems. The reliability of a system depends on how the components are interconnected. Several methods for computing system reliability are presented below. 9.1.1 Series Svstems The simplest type system is a series system in which every conipo-nent must function if the system is to function (see Fig. 9.1.1). Considering the random variable of the time of failure as Ti for the i-th component, then for a system of n components, the system reliability over the period (0, t) is n n i = l i = l R 3 (t) = n P ( T i> t) = I1 Ri(t) (9.1.1) where Ri(t) is the reliability for the i-th component. For a system that has failure times exponentially distributed (with constant failure rates) so that the i-th component reliability is em%', then the system reliability i