Estabilidade aerodinâmica de estruturas: aplicação à análise de tabuleiros de pontes

Miguel de Morais

Key information

Authors:

Miguel de Morais (Miguel de Morais Tavares)

Supervisors:

Fernando Manuel Fernandes Simões (Fernando Manuel Fernandes Simões); António Manuel Figueiredo Pinto da Costa (António Manuel Figueiredo Pinto da Costa)

Published in

November 9, 2012

Abstract

The results of an algorithm implemented to obtain the conditions for the occurrence of aerodynamic instability by flutter in slender structures, namely bridges with slender cross sections, are presented and discussed in this dissertation. The formulation which was in the basis of the numerical analysis program developed using MATLAB is introduced. The most important dimensionless parameters characterizing the occurrence of instability are shown as well. In order to validate the algorithm implemented in the scope of this dissertation a comparison is made between the results obtained with those of scientific papers. In a first approach we have implemented the algorithm for a two-degrees of freedom model. Making use of this program, abacuses for the evaluation of flutter susceptibility of real bridge deck sections were built. Another type of aerodynamic instability that affects slender structures, divergence instability, is also discussed. A more complex algorithm to solve three-dimensional problems, including an airfoil and a cable bridge similar to Jiangyin suspension bridge was also implemented. One of the most interesting conclusions of this work is the consistency of the results between the two models (two-dimensional and three-dimensional), suggesting that simplified models with two degrees of freedom are enough to obtain a good estimate of the susceptibility to aerodynamic instability. Finally, some suggestions for future research are made, particularly on the modeling of aerodynamic forces and on the different approaches that can be made to this problem (frequency domain versus time domain).