Controle de vibração em pórticos utilizando absorverdores dinâmicos de vibração ; Vibration control in frames using dynamic vibration absorbers

The advancement of science and technology in the area of civil construction has provided the construction of slimmer works with larger spans, but when excited by dynamic loading they are subject to excessive vibration, which causes discomfort to users and reduces the structure's useful life. The aim of this dissertation was to study Dynamic Vibration Absorbers (DVA's) devices, analyzing their influence and effectiveness in controlling the vibrations of frame-type structures. For this, a numerical dynamic analysis of the primary structure was performed to identify the frequency response function and the first modes of vibration, using the Finite Element Method (FEM) and ANSYS® software. From this analysis, the ideal parameters of the device were determined: stiffness, the mass ratio between the mass of the DVA and the primary structure, and the damping to control the frame's first natural frequency. Two frames were analyzed, the first with one floor and the other with three floors. The DVA's were modeled as a free beam with concentrated mass at the tip, using the Euler-Bernoulli equation. These DVA's were coupled to the structures and the same numerical analyzes were carried out, in which a reduction in the displacement amplitude was observed. For the three-story frame, the analysis of the coupling position of the DVA in the primary structure was performed and it was found that when positioning the DVA on the third floor, a place with greater displacement amplitudes, the device was more efficient in controlling vibrations. The DVA with a mass ratio of 25.00% showed the best performance in reducing the amplitude of vibrations in the two cases studied. Other values of mass ratios were also investigated and the devices also reduced the displacement amplitudes when coupled to the primary structure, showing that DVA's are efficient devices for controlling vibrations of the first vibrating mode of the structures studied in this dissertation. ; O avanço da ciência e tecnologia na área da construção civil proporcionou a ...