Vibrações não lineares de colunas esbeltas parcialmente enterradas

• Ano de defesa: 2019
• Autor(a) principal: Pires Filho, Leyser Pacheco
• Orientador(a): Del Prado, Zenón José Guzmán Nuñez
• Banca de defesa: Del Prado, Zenón José Guzmán Nuñez, Silva, Frederico Martins Alves da, Ávila, Suzana Moreira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Geotecnia, Estruturas e Construção Civil (EEC)
• Departamento: Escola de Engenharia Civil - EEC (RG)
• País: Brasil
• Palavras-chave em Português: Colunas parcialmente enterradas; Base elástica; Winkler; Pasternack; Vibrações não lineares
• Palavras-chave em Inglês: Partially embedded columns; Elastic base; Winkler; Pasternack; Nonlinear vibrations
• Área do conhecimento CNPq: ESTRUTURAS::MECANICA DAS ESTRUTURAS
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/9564

In this work the nonlinear vibrations of partially embedded slender columns subjected to axial and lateral loads are studied. The thin column is modelled by the nonlinear Euler-Bernoulli theory e the soil behavior is described by two models: the Winkler model, which considers the load proportional to the column deflection, and the Pasternack model, which takes into account two different stiffness parameters to describe the elastic base. The equations of motion of the column are derived from the energy functionals through the application of the Rayleigh-Ritz method along with the Hamilton principle and, afterwards, are solved by the convenient method for each analysis. It is accomplished a convergence study for the natural frequencies of the column in order to assess qualitatively the response from each elastic base model. The post-critical and amplitude- frequency relationship curves are obtained, allowing to understand how the system stiffness varies with the increase of axial load and frequency amplitude, respectively. From the solution of the equations of motion by the forth order Runge-Kutta method, the resonance curves, the parametric instability and escape boundaries, the bifurcation diagrams and associated phase portraits are obtained, enabling identifying in what ways the elastic base parameters from each model affect the nonlinear vibrations of the column partially embedded. Lastly, it is presented a brief study about the dynamic amplification in the column response when the lateral load is applied as an impact.