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Model Refinement Using Eigensystem AssignmentThis paper presented a novel approach for the refinement of finite-element-based analytical models of flexible structures is presented. The proposed approach models the possible refinements in the mass, damping, and stiffness matrices of the finite element model in the form of a constant gain feedback with acceleration, velocity, and displacement measurements, respectively. Once, the free elements of the structural matrices have been defined, the problem of model refinement reduces to obtaining position, velocity, and acceleration gain matrices, which reassign a desired subset of the eigenvalues of the model, along with partial mode shapes, from their baseline values to those obtained from system identification test data. A sequential procedure is used to assign one self-conjugate pair of closed-loop eigenvalues at each step using symmetric output feedback gain matrices, and the closed-loop eigenvectors are partially assigned, while ensuring that the eigenvalues assigned in the previous steps are not disturbed. The procedure can also impose that gain matrices be dissipative in order to guarantee the stability of the refined model. A numerical example, involving finite element model refinement for a structural testbed at NASA Langley (CSI Evolutionary Model) is presented to demonstrate the feasibility of the proposed approach.
Document ID
20040090576
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Maghami, Pieman G.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 1998
Subject Category
Numerical Analysis
Report/Patent Number
AIAA Paper 98-4441
Distribution Limits
Public
Copyright
Public Use Permitted.
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