ISSN: 1546-962X
CODEN: JAIOAD
Published Online: 30 August 2004
Page Count: 18

Effect of Individual Component Life Distribution on Engine Life Prediction

Zaretsky, EV
Chief Engineer for Structures and Acoustics, National Aeronautics and Space Administration, Glenn Research Center, Cleveland, OH

Hendricks, RC
Senior Technologist, National Aeronautics and Space Administration, Glenn Research Center, Cleveland, OH

Soditus, SM
Senior Engineer, United Airlines Maintenance, San Francisco, CA

(Received 9 September 2002; accepted 20 August 2003)

Abstract

The effect of individual engine component life distributions on engine life prediction was determined. A Weibull-based life and reliability analysis of the NASA Energy Efficient Engine was conducted. The engine's life at a 95 and 99.9 % probability of survival was determined based on the engine manufacturer's original life calculations and assumed values of each of the component's cumulative life distributions as represented by a Weibull slope. The lives of the high-pressure turbine (HPT) disks and blades also were evaluated individually and as a system in a similar manner. Knowing the statistical cumulative distribution of each engine component with reasonable engineering certainty is a condition precedent to predicting the life and reliability of an entire engine. The life of a system at a given reliability will be less than the lowest-lived component in the system at the same reliability (probability of survival). Where Weibull slopes of all the engine components are equal, the Weibull slope had a minimal effect on engine L0.1 life prediction. However, at a probability of survival of 95 % (L5 life), life decreased with increasing Weibull slope.

Keywords:
engine life, Weibull analysis, turbine, blade, disk reliability

Paper ID: JAI11577
DOI: 10.1520/JAI11577
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