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Rotating Beams and Nonrotating Beams With Shared Eigenpair.

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Title: Rotating Beams and Nonrotating Beams With Shared Eigenpair.
Authors: Kumar, Ananth1 ae05b004@iitm.ac.in, Gangu, Ranja2 ganguli@aero.iisc.ernet.in
Source: Journal of Applied Mechanics. Sep2009, Vol. 76 Issue 5, p051006:1-051006:14. 14p. 9 Charts, 22 Graphs.
Subjects: Girders, Finite element method, Cantilevers, Stiffness (Mechanics), Military strategy
Abstract: In this paper we look for rotating beams whose eigenpair (frequency and mode-shape) is the same as that of uniform nonrotating beams for a particular mode. It is found that, for any given mode, there exist flexural stiffness functions (FSFs) for which the jth mode eigenpair of a rotating beam, with uniform mass distribution, is identical to that of a corresponding nonrotating uniform beam with the same length and mass distribution. By putting the derived FSF in the finite element analysis of a rotating cantilever beam, the frequencies and mode-shapes of a nonrotaring cantilever beam are obtained. For the first mode, a physically feasible equivalent rotating beam exists, but for higher modes, the flexural stiffness has internal singularities. Strategies for addressing the singularities in the FSFforfinite element analysis are provided. The proposed functions can be used as test-functions for rotating beam codes and for targeted destiffening of rotating beams. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:In this paper we look for rotating beams whose eigenpair (frequency and mode-shape) is the same as that of uniform nonrotating beams for a particular mode. It is found that, for any given mode, there exist flexural stiffness functions (FSFs) for which the jth mode eigenpair of a rotating beam, with uniform mass distribution, is identical to that of a corresponding nonrotating uniform beam with the same length and mass distribution. By putting the derived FSF in the finite element analysis of a rotating cantilever beam, the frequencies and mode-shapes of a nonrotaring cantilever beam are obtained. For the first mode, a physically feasible equivalent rotating beam exists, but for higher modes, the flexural stiffness has internal singularities. Strategies for addressing the singularities in the FSFforfinite element analysis are provided. The proposed functions can be used as test-functions for rotating beam codes and for targeted destiffening of rotating beams. [ABSTRACT FROM AUTHOR]
ISSN:00218936
DOI:10.1115/1.3112741