Cost benefit analysis of a two non-identical unit standby system with two repairmen and repair machine failure

Abstract

The paper analyses a two non-identical unit (unit-1 and unit-2) cold standby system model in respect of reliability and cost effectiveness indices. Unit-1 gets priority in operation and has two modes of operation- Normal and Quasi-normal (not as good as new). Two repairmen ordinary and skilled are always available with the system to repair and complete overhaul respectively. A repair machine is used to repair the unit-1 when it fails first time and after repair, it goes into quasi-normal mode. Again, when unit-1 fails from quasi-normal mode, it goes for complete overhaul and then it becomes as good as new. The unit-2 always needs complete overhaul upon its failure and becomes as good as new after this maintenance action. The repair time distribution of unit-1 (failed first time) is taken as general whereas the distributions of other random variables denoting failure and repair /complete overhaul of a unit or RM are taken exponential with different parameters.