Joint Optimization for the Spare Part Support System Location-Inventory-Allocation Problem under (T, S) Policy

Inventory management and material distribution are two important events that need to be properly determined in the spare part support system. Therefore, it is of great importance for decision-makers to provide a feasible scheme for programming the depot locations, inventory parameters, and distribution patterns for the spare part supply chain. To this end, a location-inventory-allocation model is devised with the objective to minimize the total cost including construction expense, transporting expenditure, order outlay, inventory and shortage payment under supply availability, fill rate, and the expected delay time indicators as constraints. Considering the periodical character of spare parts maintenance, the periodic review order-up-to-S
$(\mathbf{T},\ \mathbf{S})$
policy is encoded in the model. To further facilitate model optimization, a revised model based on the Economic Order Quantity (EOQ) function is devised with
$(\mathbf{T}, \mathbf{R},\ \mathbf{S})$
policy as the inventory strategy. The demands of the operation sites are supposed as random variables with lead time set as a constant. Finally, a numerical example is provided to verify the feasibility and effectiveness of the model, and the genetic algorithm is encoded into the problem for model solving.