| For many organizations (particularly those which are capital intensive, e.g. mining, utilities, defence, heavy industries) spare parts stockholding is critical to business success.; The management of spare parts inventories requires a balance between the costs of stocking the parts and the costs and risks of not having them when they are needed. In order to achieve this balance, one has to acknowledge that spare parts inventories are governed by the reliability characteristics of the equipment and the ongoing maintenance policies.; However, there has been little integration between the areas of maintenance and reliability engineering and that of inventory and logistics, as examples of stockholding decisions with respect to maintainability or reliability parameters are, in general, scarce. Through this thesis, we develop tools to achieve the integration of these areas in an effort to close the gap between them, thus providing the maintenance community with several models directed to optimize stockholding decisions for spare parts. We concentrate on single-echelon and stochastic inventory models for non-repairable and repairable parts. Furthermore, we focus on the analysis of inventories of critical and expensive spare parts, which merit the use of complex optimization models.; The contributions of this research are the following. First, we present a simple procedure for the prioritization of spare parts, directed to help managers focus their attention into the most critical parts. Second, we introduce an expedited repair inventory model with state-dependent arrivals, considering repair capacity constraints. Also in the consideration of expedited repair, we apply a dynamic control model for the service rate in a single server queue to the spare parts problem, and extend it to a more realistic cost structure. Third, we present a model that combines internal condition information of a component with the decision of ordering a spare part, in the context of a condition-based maintenance strategy.; In addition, we thoroughly discuss (and in some cases extend) several other spare parts inventory models under a common perspective and using terminology familiar to maintenance and reliability engineers. We hope that such an overview, which we have not encountered in the literature, will be of value to practitioners. |
