Defining PHM, A Lexical Evolution of Maintenance and Logistics

Prognostics and health management (PHM) is an approach to system life-cycle support that seeks to reduce/eliminate inspections and time-based maintenance through accurate monitoring, incipient fault detection, and prediction of impending faults. Coupled with autonomic logistics for unprecedented responsiveness, cost effectiveness, and mission availability, PHM is largely automated in its application. Incorporating the principles of condition-based maintenance (CBM) along with the tenets of reliability-centered maintenance (RCM), the PHM paradigm extends these capabilities and provides a robust environment to optimize maintenance and logistics for increased operational availability (A0), and reduced life-cycle costs (LCC) while potentially increasing the reliability and life expectancy of mechanical, structural, and electronic systems. Driven by a demand for greater reliability at reduced cost and fueled by technological advancements, the PHM contribution to an already robust and confounding vocabulary surrounding maintenance and logistics is significant. As adopters of PHM technology attempt to define requirements and performance parameters, difficulties encountered with various non- standardized terminology indicate that the PHM vocabulary merits a lexical review. This paper will provide a compendium of PHM terminology along with definitions and examples, derived from the authors' experience in the implementation of PHM systems. Coalescing existing vocabularies and introducing, formally, the new lexicon of maintenance and logistics, the authors seek to aid in clarification of the emerging dialogue of life-cycle support.