Título: | INFLUENCE OF VISCOELASTICITY AND SHEAR ON THE DYNAMIC STABILITY OF BEAMS AND TUBES | ||||||||||||||||||||||||||||||||||||||||
Autor: |
OSCAR FABRICIO ZULETA INCH |
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Colaborador(es): |
RAUL ROSAS E SILVA - Orientador |
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Catalogação: | 12/AGO/2014 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||||||||||||||||||||||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=23309&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=23309&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.23309 | ||||||||||||||||||||||||||||||||||||||||
Resumo: | |||||||||||||||||||||||||||||||||||||||||
Structures with non-conservative loads can lose stability either by
divergence, when static response amplitude increases monotonically, or by flutter,
through oscillations with exponentially increasing amplitudes. Several aspects
concerning the influence of damping and shear on the dynamic stability of beams
and tubes are studied. A special-purpose computer program has been developed,
enabling critical loads and time history responses to be obtained applying the
finite element method to formulation of the equations. Results of Euler-Bernoulli
and Timoshenko beams are compared for a number of alternative formulations of
proportional and viscoelastic damping. Tubes are modeled with tridimensional
elements implemented with additional incompatible modes. Viscoelastic damping
is introduced in the constitutive relations of the material, acting on deviatoric
strains. Flutter loads are calculated through the characteristic eigenvalue problem
obtained applying the Laplace’s transform to the momentum equation. In the
dynamic analysis an implicit method is used for time integration and a second
order algorithm is used in the integration of viscoelastic constitutive relations. The
results show that, for some types of damping, the responses obtained taking into
account shear strains change qualitatively the behavior of the flutter load,
including certain paradoxical phenomena, as damping is increased.
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