An optimal age-replacement policy for a cold standby repairable system with priority in use and repair

ABSTRACTIn this paper, a cold standby repairable system consisting of two dissimilar components and one repairman is studied. Assume that Component 2 after repair is ‘as good as new’ while Component 1 after repair is not, but Component 1 has priority in use and repair. Under these assumptions, using a geometric process, we consider a replacement policy based on Component 1 age T as the system age under which the cold standby system is replaced when the system age reaches T. Our problem is to determine an optimal replacement policy T* such that the average cost rate of the system is minimised. The explicit expression of the average cost rate is derived, the corresponding optimal replacement policy T* can be determined analytically or numerically. Finally, a numerical example is given to illustrate the model developed, and some sensitivity analysis on the optimal solution is also conducted.