A PERTURBATION METHOD FOR INVERSE FREQUENCY MODIFICATION OF DISCRETE,UNDAMPED SYSTEMS

Citation
Mj. Smith et Sg. Hutton, A PERTURBATION METHOD FOR INVERSE FREQUENCY MODIFICATION OF DISCRETE,UNDAMPED SYSTEMS, Journal of applied mechanics, 61(4), 1994, pp. 887-892
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Mechanics
Journal title
ISSN journal
0021-8936
Volume
61
Issue
4
Year of publication
1994
Pages
887 - 892
Database
ISI
SICI code
0021-8936(1994)61:4<887:APMFIF>2.0.ZU;2-J
Abstract
A method is described for determining the stiffness and mass modificat ions required in order to modify the natural frequencies of undamped d iscrete nongyroscopic vibrating systems in a prescribed manner. The me thod is based upon a new perturbation formulation. Structural changes are represented by perturbed stiffness and mass matrices defined in te rms of linear design parameters of the discrete model. The equations a re subject to frequency constraints defined by the analyst, and the mo dified mode shapes are assumed confined to a subspace of the baseline modes. The proposed method provides a complete solution of the perturb ation equations without deleting or approximating coupling terms in th e unknowns and is therefore suitable for large and small changes alike . Numerical results demonstrate that the new method is superior to the predictor-corrector method for determining large structural changes a nd that solutions of a high accuracy can be obtained provided a suffic iently rich subspace of baseline modes is used.