Optimal joint spare stocking and age based replacement policy

In allusion to the characteristic of spare part demand of a single-unit system under age replacement policy, a joint optimization of age replacement policy and spare part inventory-control model (T, t₀, S) is presented, where T is preventive replacement interval, t₀ is inventory replenishment cycle length and S is the maximum stock level. In this model, by analysis the effective of life distribution of a system caused by the preventive replacement interval and the maximum stock level, the relationship between the total cost per unit time and the preventive replacement interval, the inventory replenishment cycle length and the maximum stock level are established. To minimize the total cost per unit time, the preventive replacement interval T, the inventory replenishment cycle length t₀ and the maximum stock level S are optimized. Matlab is utilized to gain the numerical solution of the model, and the result shows that the proposed method can effectively decrease the total cost per unit time.