Assessing Maintenance Cost for Design or Re-Design of Complex Machinery

Abstract

Maintenance costs are often significant for complex machinery, and organizations that are able to accurately assess maintenance costs for complex machinery can design or re-design the machinery to reduce maintenance expenses. This paper provides a review of relevant reliability theory to provide a background for model construction. The maintenance cost model is then developed from a probabilistic perspective, with a hierarchical breakdown of the complex machinery, and with consideration of the time value of money. A framework for the cost model is offered in which the cost of repair and preventative maintenance is considered along with the downtime costs for repair or preventative maintenance. As a proof of concept, maintenance costs for Ship Service Gas Turbine Generators (SSGTG) are developed from the Navy’s OARS (Open Architecture Retrieval System) data. Problems with data quality and heuristic adjustment of the data are discussed, recognizing that work is ongoing to improve the quality of the Navy’s maintenance data. Cognition Corporation’s Cost Advantage software is used for the modeling effort, providing an ability to focus on maintenance cost at any level of detail and to obtain cost roll up, as needed. Conclusions are drawn with respect to the modeling of maintenance costs for complex machinery.