Availability analysis of a complex system consisting of two subsystems in parallel configuration with replacement at failure

In this paper, investigation of the profit of parallel system consisting of two subsystems A and B is carried out. Each of the subsystem consists of two dissimilar components in active parallel. Two different replacement models are considered. Model 1 addresses the availability of the system by considering group replacement of the two subsystems at the system failure. Model 2 addresses the availability of the system by considering individual replacement of subsystem at its failure. In order to examine the validity of the models introduced and conduct sensitivity analysis, some diagrams are drawn for each model. Through the linear differential difference equation, explicit expressions for steady state availability for the two models are derived. Numerical examples are presented to illustrate the obtained results and to analyse the effect of group and individual replacement on the availability.