Vibrações não lineares em tubulações com fluido em escoamento

• Autor(a) principal: Prado, Joaquim Orlando
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/0013000002t7j
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/6759
• topic: Sistema não linear; Galerkin; Curvas de escape; Diagrama de bifurcação; Movimentos quase periódicos; Movimentos caóticos; Nonlinear system; Galerkin; Stability boundaries; Bifurcation diagram; Quasi-periodic motions; Chaotic motions; ENGENHARIA CIVIL::ESTRUTURAS

In this work, the linear and nonlinear instability of pipes conveying static and pulsating fluid flow is analyzed. The dynamic equation of motion was derived for cantilevered and clamped-clamped pipes. For this purpose, the Euler Bernoulli beam theory and Hamilton’s principle were applied, resulting in a partial differential equation of second order in time. Thus, a model with four degrees of freedom, which satisfies the boundary condition, is used and, the Galekin method is applied to derive the set of coupled non linear ordinary equations of motion which are, in turn, solved by the fourth order Runge-Kutta method, and then some numerical results were obtained as Argand diagram, stability boudaries, time response, phase plane and, Poincaré section, through computational algorithms modeled in C++. These results revealed the importance of the nonlinear terms in the stability of the system, especially in the post-critical analysis, also revealed the existence of quasi-periodic motions, for the system subjected to a static flow and, chaotic motions for pulsating fluid flow