REFINING COMPLEX FREQUENCIES OF VIBRATING STRUCTURES
DOI:
https://doi.org/10.26512/ripe.v2i20.15003Resumo
In structural analysis, and related, the computation of natural frequencies of vibrating systems given by its mass, damping and stiffness matrices, when at least one of this matrices is dense and the matrix size is not prohibitively large, is usually done through reduction to a generalized first order system. The QZ iteration method is then applied to achieve the Generalized Schur form, from where all the natural frequencies, and associated mode shape vectors, can be
taken from, as eigenvalues and eigenvectors of some mathematical problem. As a drawback, this reduction not only increases by a factor of 2 the sizes of the working matrices, but also allows important properties like positive definiteness (or semi-definiteness), and even symmetry, to be lost. Even further, it must be considered the fact that the condition number of the new problem (as an upper bound for the ratio between changes in the solution and changes in the data, by
means of matrix and vector norms) usually increases, sometimes by a large amount. This work investigates how the final computation of complex-valued system eigenvalues (and then complex system frequencies) can take advantage of an iterative refinement technique, based in a shifted and inverted Krylov-type strategy that uses the original linear second-order matrices, in the same computational environment. The proposed strategy takes advantage that, in its original second-order form, the eigenvalue problem seams to be far better conditioned and well suited for high performance computations than in the generalized first-order form. The proposed strategy is applied to some test matrices from the Harwell-Boeing Collection of the Matrix Market
website. Numerical examples using professional software are also provided.
Keywords: second-order, complex frequency, vibration, structure
Downloads
Referências
E. Anderson, et al., 1999. LAPACK User’s Guide. Third Edition, SIAM.
Z. Bai and Y. Su, 2005. SOAR: A second-order Arnoldi method for the solution of the quadratic eigenvalue problem, SIAM J. Matrix Anal. Appl., vol. 26, n.3, 640”“659 , DOI:10.1137/S0895479803438523.
J. Carvalho and J. Claeyssen, 2011. Computation of extreme clustered natural frequencies of damped second-order linear systems, Proceedings of Conferˆencia Brasileira de Dinˆamica, Controle e Aplicac¸ ˜oes, vol. 1, 454”“457.
J. Carvalho and J. Claeyssen, 2013. Refining natural frequencies of damped linear vibrating structures, Proceedings of 34th Ibero-Latin American Congress on Computational Methods in Engineering.
J. Claeyssen, 1990. On predicting the response of nonconservative linear vibrating systems by using dynamical matrix solutions, J. Sound and Vibration, vol. 140, 73”“84.
S. Eisenstat and I. C. Ipsen, 1998. Three absolute perturbation bounds for matrix eigenvalues imply relative bounds. SIAM J. on Matrix Analysis and Appl., vol. 20, n. 1, 149”“158, DOI:10.1137/S0895479897323282.
G. Golub and C. Van Loan, 1996. Matrix computations, Johns Hopkins University Press, Baltimore, MD, USA.
D. Higham and N. Higham, 1999. Structured Backward Error and condition of generalized eigenvalue problems, SIAM J. Matrix Anal. Appl, vol. 20, n.2, 493”“512, DOI:10.1137/S0895479896313188.
G. Sleijpen and H. VanderVorst, 1996. A Jacobi-Davidson iteration method for linear eigenvalue problems, SIAM J. Matrix Anal. Appl., vol. 17, 401”“425, DOI:10.1137/S0036144599363084.
A. Sondipon, 1999. Rates of change of eigenvalues and eigenvectors in damped dynamic system, AIAA Journal, vol. 37, n.11, 1452”“1458, DOI: 10.2514/2.622.
G. W. Stewart, 1972. On the Sensitivity of the Eigenvalue Problem Ax = Bx. SIAM J. on Numerical Analysis vol. 9, n.4, 669”“686, DOI:10.1137/0709056.
A. Varga, 1990. Computation of irreducible generalized state-space realizations, Kybernetika, vol. 26, 89”“106, DOI: 10.1.1.539.2629.
Y. Zhou, 2006. Studies on Jacobi-Davidson, Rayleigh quotient iteration, inverse iteration generalized Davidson and Newton updates, Numerical Linear Algebra with Applications, vol.13, 621”“642, DOI: 10.1002/nla.490.
The Matrix Market directory on the web. Online reference and repository at http://math.nist.gov/MatrixMarket.
Downloads
Publicado
Como Citar
Edição
Seção
Licença
Autores que publicam nesta revista concordam com os seguintes termos:
Autores mantém os direitos autorais e concedem à revista o direito de primeira publicação, sendo o trabalho simultaneamente licenciado sob a Creative Commons Attribution License o que permite o compartilhamento do trabalho com reconhecimento da autoria do trabalho e publicação inicial nesta revista.
Autores têm autorização para assumir contratos adicionais separadamente, para distribuição não-exclusiva da versão do trabalho publicada nesta revista (ex: publicar em repositório institucional ou como capítulo de livro), com reconhecimento de autoria e publicação inicial nesta revista.
Autores têm permissão e são estimulados a publicar e distribuir seu trabalho online (ex: em repositórios institucionais ou na sua página pessoal) a qualquer ponto antes ou durante o processo editorial, já que isso pode gerar alterações produtivas, bem como aumentar o impacto e a citação do trabalho publicado.