The U.S. Navy has developed a usage monitoring system based on the regime recognition concept for tracking rotary wing aircraft fatigue components and structures. Thus far, 50 AH-1W aircraft have been equipped with the Structural Data Recording Set (SDRS), acquiring 3400 valid flight hours of usage. The usage variations in each regime are modeled using a Weibull distribution. Similarly, the load variations in each regime are also modeled using a Weibull distribution. The strength variation was obtained from the aluminum alloy-264 full-scale component fatigue test data. This variation is modeled using a Weibull distribution. The usage, load, and strength variations are then combined to compute fatigue life and the associated multivariate probability of failure and reliability. The component fatigue lives versus the reliability curve will help the U.S. Navy plan component retirements with specified risks. In addition, the individual contribution from usage, loads, strength, and cycle counting to six nines reliability are calculated. Finally, the impact of usage monitoring on reliability is assessed and the bivariate standard deviation required to achieve six nines reliability is evaluated.
Fatigue life reliability based on measured usage, flight loads, and fatigue strength variations
Zuverlässigkeit der Ermüdungslebensdauer basierend auf Messungen, Fluglasten und variablen Dauerschwingfestigkeiten
Journal of the American Helicopter Society ; 56 , 3 ; 032006/1-032006/18
2011
1 Seite, 27 Bilder, 10 Tabellen, 12 Quellen
Article (Journal)
English
Fatigue Life Reliability Based on Measured Usage, Flight Loads, and Fatigue Strength Variations
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