Solution procedure for a repair-limit problem using the total time on test (TTT) concept

We address the problem of controlling the repair-time limit of a one-unit repairable system in order to minimize the total expected cost for one cycle, when repair time is random. The underlying theoretical problem is reduced to the geometrical one using the TTT concept. We obtain the optimal repair-limit policy analytically/graphically and show that the optimal solution is calculated simply from the complete data of repair time without specifying the distribution function. We also develop computer software to obtain the optimal repair-limit policy numerically, and illustrate its use by examples.