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Time simulation of flutter with large stiffness changesTime simulation of flutter, involving large local structural changes, is formulated with a state-space model that is based on a relatively small number of generalized coordinates. Free-free vibration modes are first calculated for a nominal finite-element model with relatively large fictitious masses located at the area of structural changes. A low-frequency subset of these modes is then transformed into a set of structural modal coordinates with which the entire simulation is performed. These generalized coordinates and the associated oscillatory aerodynamic force coefficient matrices are used to construct an efficient time-domain, state-space model for basic aeroelastic case. The time simulation can then be performed by simply changing the mass, stiffness and damping coupling terms when structural changes occur. It is shown that the size of the aeroelastic model required for time simulation with large structural changes at a few a priori known locations is similar to that required for direct analysis of a single structural case. The method is applied to the simulation of an aeroelastic wind-tunnel model. The diverging oscillations are followed by the activation of a tip-ballast decoupling mechanism that stabilizes the system but may cause significant transient overshoots.
Document ID
19920051843
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Karpel, M.
(Technion - Israel Institute of Technology Haifa, United States)
Wieseman, C. D.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1992
Subject Category
Structural Mechanics
Report/Patent Number
AIAA PAPER 92-2394
Meeting Information
Meeting: AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
Location: Dallas, TX
Country: United States
Start Date: April 13, 1992
End Date: April 15, 1992
Accession Number
92A34467
Funding Number(s)
CONTRACT_GRANT: NAS1-18605
CONTRACT_GRANT: NAGW-1708
Distribution Limits
Public
Copyright
Other

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