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Deflection-Based Aircraft Structural Loads Estimation with Comparison to FlightTraditional techniques in structural load measurement entail the correlation of a known load with strain-gage output from the individual components of a structure or machine. The use of strain gages has proved successful and is considered the standard approach for load measurement. However, remotely measuring aerodynamic loads using deflection measurement systems to determine aeroelastic deformation as a substitute to strain gages may yield lower testing costs while improving aircraft performance through reduced instrumentation weight. With a reliable strain and structural deformation measurement system this technique was examined. The objective of this study was to explore the utility of a deflection-based load estimation, using the active aeroelastic wing F/A-18 aircraft. Calibration data from ground tests performed on the aircraft were used to derive left wing-root and wing-fold bending-moment and torque load equations based on strain gages, however, for this study, point deflections were used to derive deflection-based load equations. Comparisons between the strain-gage and deflection-based methods are presented. Flight data from the phase-1 active aeroelastic wing flight program were used to validate the deflection-based load estimation method. Flight validation revealed a strong bending-moment correlation and slightly weaker torque correlation. Development of current techniques, and future studies are discussed.
Document ID
Document Type
Preprint (Draft being sent to journal)
Lizotte, Andrew M. (NASA Dryden Flight Research Center Edwards, CA, United States)
Lokos, William A. (NASA Dryden Flight Research Center Edwards, CA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2005
Subject Category
Aircraft Design, Testing and Performance
Meeting Information
46th Structures, Structural Dynamics and Materials Conference(Austin, TX)
Distribution Limits
Work of the US Gov. Public Use Permitted.

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