Instabilidade dinâmica de cascas cilíndricas viscoelásticas

• Autor(a) principal: Martins, Nickollas Pereira
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/9759
• topic: Cascas cilíndricas; Instabilidade dinâmica; Modelo Kelvin-Voigt; Cylindrical shels; Viscoelastic material; Dynamic instability; Kelvin-Voigt model; ENGENHARIA CIVIL::ESTRUTURAS

Cylindrical shells are a type of structures that exhibit good mechanical behavior, such as, great load capacity and reserve strength, for this reason shells are widely used in several areas of engineering. Due to intrinsic advantages to this type of structures, researches in this field have been developed aiming the better understanding of the complex dynamic behavior of this kind of structures. Aiming the improvement of the better understanding of shell, in the present work is shown a study over the influence of viscoelasticity on the dynamic response of the structure by the introduction of the Kelvin-Voigt constitutive model; in addition, the shell is described by Donnell’s shallow shell theory. Using a numerical approach the partial differential equation is solved by the expansion of the transversal behavior in six modes then the Galerkin’s method is applied to obtain a system of differential equations that is solved by Runge-Kutta’s method. The study of the structure is done by means of some tools of dynamics such as time response, bifurcation diagrams, Poincaré maps, phase planes, resonance curve, parametric instability curve and basins of attraction. The results showed that the shell’s nonlinear behavior is strongly influenced by de viscoelastic dissipation parameter and that the stability of the shell is increased when the viscous forces are taking into account.