Volume 1, Issue 8 (September 2004)
Effect of Individual Component Life Distribution on Engine Life Prediction
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.