A method for quantifying the reliability and damage tolerance of aircraft composite structures due to flutter in the presence of multiple uncertainties was presented in this paper. Automated rapid simulation tools for predicting flutter speeds for composite airframes subject to multiple uncertainties (our VATM capabilities) serve a key role and are used in Monte Carlo simulations. The effectiveness of the method is illustrated on a typical composite aircraft tail/rudder structure. Conclusions of the exploratory studies reported here include the following: 1) Probabilistic methods may be used effectively to quantify the flutter reliability of composite aircraft structures, thus enabling aircraft manufacturers, operators, and flight certification authorities to establish design, maintenance, and service guidelines that reduce life-cycle cost. 2) The inspection interval that insures a reasonably high reliability depends primarily on the statistical characteristics of external loads and flight speeds; damage rates, types, inspection, and repair; and both residual static strength and stiffness of the damaged structure. 3) The most uncertain variables in any probabilistic damage-tolerance design method are damage size and frequency. To obtain in-service data that contain complete descriptions of damage size and frequency, structural locations, inspection methods, and repair used is still a major challenge, but it is of major importance. 4) Additional studies of different structural airframe configurations are required. In particular, horizontal tail/elevator/tab systems, wing/control surface systems, and complete aircraft. Effects of hinge failure and possible failure of internal structure should also be considered. Other modes of failure due to aeroelastic behavior should be studied too, such as dynamic stresses due to gust excitation and the fatigue effects of LCOs. The methodology presented here and the associated simulation tools can be extended to cover all such cases.
Flutter failure risk assessment for damage-tolerant composite aircraft structures
Bewertung des Flatterausfallrisikos für schadenstolerante Verbundflugzeugkonstruktionen
AIAA Journal ; 49 , 3 ; 655-669
2011
15 Seiten, 18 Bilder, 4 Tabellen, 47 Quellen
Article (Journal)
English
Flutter Failure Risk Assessment for Damage-Tolerant Composite Aircraft Structures
Online Contents | 2011
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