Structural Engineering and Mechanics

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Sub-degrees of freedom method with perturbation procedure for reduction of eigenvalue computation

  • Liu, Xiao-Lin (Laboratorio Nacional de Engenharia Civil, Avenida do Brasil)
  • Published : 1999.12.25
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Abstract

A new way to reduce the eigenvalue computation effort in structural dynamics is presented in this paper. The degrees of freedom of a structure may be classified into groups that are termed as sub-degrees of freedom. The eigenvalue analysis is performed with each of sub-degrees of freedom so that the computing time is much shortened. Since the dynamic coupling between sub-degrees of freedom is selected to be small and it may be considered as a perturbation, the perturbation algorithm is used to obtain an accuratae result. The accuracy of perturbation depends on the coupling between sub-degrees of freedom. The weaker the coupling is, the more accurate the result is. The procedure can be used to simplify a problem of three dimensions to that of two dimensions or from two dimensions to one dimension. The application to a truss and a space frame is shown in the paper.

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References

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Cited by

  1. Derivation of formulas for perturbation analysis with modes of close eigenvalues vol.10, pp.5, 2000, https://doi.org/10.12989/sem.2000.10.5.427