A Presentation on Robust Flutter Margin Analysis and a Flutterometer

Lind, Rick C. (1997) A Presentation on Robust Flutter Margin Analysis and a Flutterometer. Technical Report NASA/TM-97-206220, Research Engineering, NASA Dryden Flight Research Center.

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Abstract

This paper documents an invited presentation given to The Boeing Company, Seattle, Washington, on September 9, 1997. The audience consisted of structural dynamic and flight test engineers from the Boeing Commercial Airplane Group who were interested in discussing research which may be applied to future flight flutter test programs. A method to compute robust flutter margins is described which is a significant departure from traditional methods. This method uses the structured singular value, mu, to compute a flutter margin which directly accounts for modeling errors such that a worst-case flutter margin is computed with respect to those errors. This method may be applied in several ways. A post-flight application uses data sets from multiple test points to compute worst-case flutter margins and a worst-case flight envelope. An on-line implementation computes flutter margins at each test point to track the flutter margins during a flight test. This on-line implementation is the basis for a flutterometer flight test tool that displays the distance to flutter at a given test point. Such a tool was not previously possible using traditional flutter flight test analysis methods. The F/A-18 System Research Aircraft was used to demonstrate these applications using flight data recorded from test points throughout the flight envelope.

EPrint Type:	NASA Technical Memorandum
Keywords:	Aeroelasticity, Flight test, Flutter, Robust stability, Structured singular value
Subjects:	(01 - 09) Aeronautics: (08) Aircraft Stability And Control Aircraft/Project: F-18 SRA
ID Code:	154
Deposited On:	10 June 2004
Additional Information:	65 pages. Oral presentation given at The Boeing Company, Seattle, Washington, on September 9, 1997. Rick C. Lind is a National Research Council research associate.