The Path to Affordable Long Term Failure Warning: The XRF-Wear Monitor.

Abstract : Long term early warning of wear related failure has recently been demonstrated for operational turbine engines. Particles recovered from Navy F/A-18 engine oil filters were analyzed for chemical elemental content using X-ray fluorescence analysis (XRF). (1) The data were compared with known engine metallurgy to determine the source of particles generated by wear, corrosion, and contamination. The identified sources agreed with engine history as recorded in the maintenance database. Normally operating engines showed low levels of wear particulates, as expected. The XRF filter debris analysis method (XRF-FDA) successfully identified every oil wetted wear-related failure as having elevated quantities of metals. Warning times in excess of 100 operating hours; and (2) were achieved through the ability of XRF to measure elements other than iron. Some engines undergoing high time replacements showed high levels of metals as expected; the method enables the low wear engines to be identified. These striking results have implications for planning of operations and maintenance. This paper presents the XRF-Wear concept for autonomous on-line monitoring of aviation engines and other high value machinery. An economically advantageous approach to assembling the wear-profile database of previously unmonitored equipment is offered in the context of a fully automated, field deployable, on-site expert system.