Age Replacement For Scheduled Vehicles With Minimum Repairs And Catastrophes

The paper attempts to identify the Optimal Preventive ReplacementInterval of Scheduled Vehicles with average cost per unit time in the meanreplacement cycle as the cost minimizer. With minimal repairs andcatastrophes, the model makes tradeoff among4time-dependent costs:(1)depreciation,(2) repairing cost of burn-in failures,(2) parts scheduledreplacement cost&repairing cost of ware-out failures and (4) fuel cost.Analytical solution was derived via model approximation. The objectivefunctions of original model and approximation model are convex and thereare3forms of optimal solutions. Among them, the optimal solution atinflection point is (1) a monotonically increasing function with vehicleprice, intensity of catastrophes and other parameters,(2) a monotonicallydecreasing function with the accelerating parameters of ware-out failuresand fuel cost and (3) a concave function with the decreasing parameter ofthe intensity of burn-in failures. The results can be applied to thereplacement problem of scheduled vehicles, such as long distance busesand public transit vehicles.