Application of Probabilistic Fracture Mechanics to Prognosis of Aircraft Engine Components

Abstract

It is generally accepted that traditional logistics functions including periodic nondestructive inspections and planned maintenance increase the reliability and readiness of turbine engines. Nevertheless, further significant enhancements in reliability and readiness are believed to be possible through the implementation of a prognosis system based on online monitoring and interpretation of critical engine operating parameters and conditions to diagnose potential problems and forecast readiness. An approach is presented for improving probabilistic life prediction estimates through the application of prognosis methods. Actual F-16/F100 usage data from flight data recorders were interfaced with a probabilistic life prediction code to quantify the influence of usage on the probability of fracture of an idealized titanium compressor disk. For the example cases considered, it is shown that usage variability leads to about 6 × × variability in life and from 10 × × to 100 × variability in the probability of fracture. The results suggest that variability in usage could provide a basis for selectively extending the life of aircraft engines.