Título: | NONLINEAR DYNAMICS, INSTABILITY AND CONTROL OF STRUCTURAL SYSTEMS WITH MODAL INTERACTION | ||||||||||||||||||||||||||||||||||||||||||||
Autor: |
DIEGO ORLANDO |
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Colaborador(es): |
PAULO BATISTA GONCALVES - Orientador GIUSEPPE REGA - Coorientador STEFANO LENCI - Coorientador |
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Catalogação: | 27/AGO/2010 | 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=16177&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=16177&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.16177 | ||||||||||||||||||||||||||||||||||||||||||||
Resumo: | |||||||||||||||||||||||||||||||||||||||||||||
The aim of this thesis is to study the influence of coupled buckling modes
on the static and particularly on the nonlinear dynamic behavior of structural
components liable to buckling. For this, two discrete two degrees of freedom
models known for their complex nonlinear behavior are selected: the well-known
Augusti’s model and a simplified model of cable-stayed tower. Initially, the
stability analysis of the perfect models is conducted, including the identification
of all pre- and post-critical equilibrium paths, and the effect of imperfections on
the load capacity of the structure and stability of the various equilibrium paths.
The purpose of this analysis is to understand how the various unstable post-critical
solutions and imperfections influence the geometry of the potential energy
surface, the contour of the pre-buckling potential well and the integrity of the
structure under the inevitable external disturbances. Then the behavior of the
models in free vibration is investigated, including the identification of the natural
frequencies, linear vibration modes and possible internal resonance. To
understand the dynamics of the models, the geometry of the safe region
surrounding the pre-buckling equilibrium position and the invariant manifolds of
saddle points that define this region are obtained using the tools of Hamiltonian
mechanics. Also, as part of the free vibrations analysis, all stable and unstable
nonlinear vibration modes and their frequency-amplitude relations are obtained.
These nonlinear stable and unstable modes, which arise due to modal coupling
and the symmetries of the models, control and explain the dynamics of the model
under forced vibration. Based on these results, we study the behavior of the
models subjected to a base excitation through a systematic study of the global and
local bifurcations, and the integrity of stable solutions through the evolution and
stratification of the basins of attraction and dynamic integrity measures. Finally,
we study how to increase the safety of the structure through the control of global
homoclinic and heteroclinic bifurcations. This thesis identifies a number of
behaviors that are typical of the two models and can be understood as
characteristic phenomena of structures exhibiting modal coupling. Thus the main
contribution of this work is to identify certain characteristics and particular
aspects of this class of structures, a first contribution to this research area.
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