AVAILABILITY ANALYSIS OF A REPAIRABLE STANDBY HUMAN-MACHINE SYSTEM

This paper presents a model representing a two units active and one un it on standby human-machine system with general failed system repair t ime distribution. In addition, the model takes into consideration the occurrence of common-cause failures. The method of linear ordinary dif ferential equation is presented to obtain general expressions for syst em steady state availability for failed system repair time distributio ns such as Gamma, Weibull, lognormal, exponential, and Rayleigh. Gener alized expressions for system reliability, time-dependent availability , mean time to failure, and system variance of time to failure are als o presented. Selected plots are presented to demonstrate the impact of human error on system steady state availability, reliability, time-de pendent availability, and mean time to failure.