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Computer-Controlled Normal Mode Testing

Sinapius, J.M. and Lake, R.C. (1999) Computer-Controlled Normal Mode Testing. In: Int'l Forum on Aeroelasticity and Structural Dynamics 1999, 1, pp. 89-99. Williamsburg, VA., U.S.A, 22.06.1999.

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Normal mode testing is a long-standing test method of experimental modal analysis. Typically, the harmonic responses of a harmonically-excited structure are investigated during normal mode testing with regard to their phase relation to the excitation. While classical phase resonance methods are suitable for checking the linearity of the structural dynamic behaviour of aerospace structures, a significant amount of time is required to perform normal mode tuning, consequently resulting in considerable costs incurred during the prototype development period. However, improvements in computer technologies and measurement techniques enable improvements in the classical phase resonance procedure, especially with regard to minimizing the test schedule without loss of accuracy of the results. This paper focuses on new methods for automated tuning and on-line data evaluation procedures for normal mode testing by investigating band-limited frequency responses for analytical and experimental vibration systems during the on-line tuning process. Three different approaches for accelerating the tuning process are investigated with respect to their on-line capabilities. In general, these methods deliver estimations about eigenfrequency, modal damping, and generalized mass, but differ in the amount of modal information delivered and, consequently, in the computational effort required. The three different methods of computer-controlled normal mode testing were experimentally verified via ground testing using the Piezoelectric Aeroelastic Response Tailoring Investigation (PARTI) testbed at NASA Langley's Transonic Dynamic Tunnel, as well as the 20m spanwidth sailplane FS-33 located at DLR. Experimental results obtained from these applications are described and initial experiences are discussed.

Item URL in elib:https://elib.dlr.de/14089/
Document Type:Conference or Workshop Item (Paper)
Additional Information: LIDO-Berichtsjahr=1999, monograph_id=CP-1999-209136,
Title:Computer-Controlled Normal Mode Testing
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Journal or Publication Title:Int'l Forum on Aeroelasticity and Structural Dynamics 1999
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Page Range:pp. 89-99
National Aeronautics and Space Administration (NASA), UNSPECIFIED
Keywords:normal mode test, experimental modal analysis
Event Title:Williamsburg, VA., U.S.A, 22.06.1999
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W SY - Technik für Raumfahrtsysteme
DLR - Research area:Space
DLR - Program:W SY - Technik für Raumfahrtsysteme
DLR - Research theme (Project):UNSPECIFIED
Location: Göttingen
Institutes and Institutions:Institute of Aeroelasticity
Deposited By: DLR-Beauftragter, elib
Deposited On:16 Sep 2005
Last Modified:14 Jan 2010 21:23

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