Modal Scaling from Known Mass Perturbations
Publication: Journal of Engineering Mechanics
Volume 130, Issue 9
Abstract
When the identification of a linear system is carried out without deterministic input information the scaling constants that connect the eigensolution to the matrices of the physical system are not determined. One way to generate information to compute these constants is by testing the structure with known modifications and examining how the eigensolution changes. Closed-form uncoupled expressions have been derived from this idea by requiring that the changes in the frequencies, or the mode shapes, be small. For general modifications, however, the solution is currently sought in the less convenient framework of a nonlinear optimization. This paper presents a new formulation that can accommodate arbitrary modifications yet retains the computational advantages of a closed-form solution. Results from a statistical simulation study suggest that the new expression is not only computationally attractive, but can lead to improvements in accuracy when compared to the existing alternatives.
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References
Bernal, D.(2002). “Load vectors for damage localization.” J. Eng. Mech., 128(1), 7–14.
Bernal D., and Gunes B. (2002). “Damage localization in output-only systems: A flexibility based approach.” Proc., 20th Int. Modal Analysis Conf. (IMAC XX), 1185–1191.
Bernal, D., and Gunes, B.(2004). “Flexibility-based approach for damage characterization: Benchmark application.” J. Eng. Mech., 130(1), 61–70.
Brinker R., and Andersen P. (2003). “A way of getting scaled mode shapes in output-only modal testing,” Proc., 21st Int. Modal Analysis Conf. (IMAC XXI), Paper No. 141 (CD-ROM).
Di Ruscio(1996). “Combined deterministic and stochastic system identification and realization: DSR—A subspace approach based on observations.” Model. Ident. Control, 17(3), 193–230.
Heylen W., Lammens S., and Sas P. (1997). Modal analysis theory and testing Leuven, Belgium.
Parloo, E., Verboven, P., Cuillame, P., and Overmeire, M. V. (2001). “Sensitivity-based mass normalization of mode shape estimates from output-only data.” Proc., Int. Conf. on Structural System Identification, 627–636.
Parloo, E., Verboven, P., Cuillame, P., and Overmeire, M. V.(2002). “Iterative calculation of nonlinear changes by first-order approximations.” Mech. Syst. Signal Process., 16(5), 757–767.
Schwarz, B., and Richardson, M. (2003). “Scaling mode shapes obtained from operating data.” Proc., 21st Int. Modal Analysis Conf. (IMAC XXI), Paper No. 256, on CD.
Van Overschee, P., and Moor, B. L. (1996). Subspace identification for linear systems: Theory, implementation, applications, Kluwer Academic, Boston.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 130 • Issue 9 • September 2004
Pages: 1083 - 1088
Copyright
Copyright © 2004 American Society of Civil Engineers.
History
Received: Jun 10, 2003
Accepted: Feb 18, 2004
Published online: Aug 16, 2004
Published in print: Sep 2004
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