Controle passivo de vibrações aplicado a um sistema estrutural incorporando um dispositivo de amortecimento friccional.

Abstract

The study of dynamic effects in structural systems has been widely explored nowadays, due to concerns about the safety of society. In the scientific/technological sphere, investigations are carried out that contribute to the control of structural vibration, in order to avoid catastrophic damage caused by dynamic loads. That said, the main objective of this work is to evaluate the vibratory behavior of a metallic structure with two degrees of freedom, through the implementation of a passive control system based on the frictional damping technique. The dissipator mechanism has actuating elements, which allow the manifestation of mechanical friction responsible for the increase in structural damping. Preliminarily, modal analysis and forced vibration analysis of the physical system were carried out, with the aim of employing analytical and numerical methodologies regarding structural dynamics and then comparing the results obtained through the application of these approaches. In this comparative analysis, the most significant error was less than 5%, ensuring consistency between the methods used. On an experimental basis, tests relating to the dynamic characterization of the frictional damping device were carried out, previously defining the intrinsic parameters for calculating the energy dissipated per charging cycle. It was found that the energy dissipated increases according to the increase in displacement established in the dynamic test. Right away, the structural responses under free vibration, forced vibration and seismic excitation were analyzed, taking into consideration different test configurations, which allowed observing the behavior of the dynamic model without and with the dissipator mechanism. In particular, forced vibration tests revealed that the passive control system showed better efficiency at the second natural frequency of the structure. Considering that the frictional moment acting on the frictional damping device varies depending on the applied normal load, the maximum percentage reductions in acceleration peaks were around 82% on the first floor, and approximately 74% on the second floor.