Inventory model for major equipment maintenance companies with fuzzy & discrete spare parts demands

To reduce spare parts inventory cost of large-scale equipment maintenance companies, an inventory model with discrete, uncertain spare parts demand using fuzzy theory was presented. In this model, the component renewal rate was denoted by using triangular fuzzy number to better address the discreteness and fuzziness of spare parts demands so as to obtain fuzzy prediction of spare parts demand. Fuzzy spare parts purchasing strategy was then set up by combining the fuzzy demand of spare part with the (t, R, S) inventory control method. This model was solved by genetic agorithm, and the optimal inspection period, maximal inventory level, order point, optimal order periods and lot-sizes were obtained. Effectiveness of this inventory model was verified by case study.