RELIABILITY-ANALYSIS OF A COMPLEX STANDBY REDUNDANT SYSTEM

In any redundant system, the state of the standby unit is usually take n to be hot, warm or cold. In this paper, we present a new model of a two unit standby system wherein the standby unit is put in cold state for a certain amount of time before it is allowed to become warm. Upon failure of the online unit, the standby unit, if in warm state, insta ntaneously starts operating online; if it is in cold state, an emergen cy switching is made which takes it to warm state (and hence online) e ither instantaneously or non-instantaneously-each with some probabilit y; if it is under repair, the system breaks down. Assuming all the ass ociated distributions to be general except that of the life time of th e standby unit in the warm state, various reliability characteristics that are of interest to reliability engineers and system designers are derived. A comprehensive cost function is also constructed and is the n optimized with respect to three different control parameters numeric ally. In addition numerical results are presented to illustrate the be haviour of the various reliability characteristics derived.