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An evaluation of higher-order modal methods for calculating transient structural responseThe present study evaluates a higher-order modal method proposed by Leung for transient structural analysis entitled the force-derivative method. This method repeatedly integrates by parts with respect to time the convolution-integral form of the structural response to produce successively better approximations to the contribution of the higher modes which are neglected in the modal summation. Comparisons are made of the force-derivative, the mode-displacement, and the mode-acceleration methods for several numerical example problems for various times, levels of damping, and forcing functions. The example problems include a tip-loaded cantilevered beam and a simply-supported multispan beam. The force-derivative method is shown to converge to an accurate solution in fewer modes than either the mode-displacement or the mode-acceleration methods. In addition, for problems in which there are a large number of closely-spaced frequencies whose mode shapes have a negligible contribution to the response, the force derivative method is very effective in representing the effect of the important, but otherwise neglected, higher modes.
Document ID
19880030231
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Camarda, Charles J.
(NASA Langley Research Center Hampton, VA, United States)
Haftka, Raphael T.
(Virginia Polytechnic Institute and State University Blacksburg, United States)
Riley, Michael F.
(PRC Kentron, Inc. Hampton, VA, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1987
Publication Information
Publication: Computers and Structures
Volume: 27
Issue: 1, 19
ISSN: 0045-7949
Subject Category
Structural Mechanics
Accession Number
88A17458
Distribution Limits
Public
Copyright
Other

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