Um estudo numérico e experimental de um absorvedor dinâmico de vibração aplicado a um pórtico reduzido de três pavimentos

Abstract

Dynamic Vibration Absorbers (DVAs) are devices used to control and attenuate unwanted vibrations in structures, buildings, machines and components. From engineering's point of view, the analysis and prediction of the dynamic behavior of vibratory movements are extremely important, since their studies seek to understand the intrinsic causes of the phenomenon, in order to reduce or eliminate its effects, and also minimize its impacts. In this context, the aim of this paper was to analyze and validate a passive Dynamic Vibration Absorber (DVA) to attenuate the vibration amplitudes associated with the first bending mode of a three-story frame. For this purpose, numerical and experimental analyses of the structure were performed using ANSYS® and dBFA Suite software. The results of these analyses provided the structure's natural frequencies and its vibration modes. This information was used to dimensionate the DVA. The absorbers were designed as cantilever beams, with a mass concentrated at the free end. For the numerical study, the device was coupled to the main structure at the point of greatest displacement amplitude, located on the third and final floor of the frame. For the experimental study, the ADV was positioned on the second floor of the structure. The bench tests used the Rational Fraction Polynomial Method (FRP) during data post-processing. Thus, the analyses showed that the DVAs were effective in reducing the vibration amplitudes in the system, achieving reduction results greater than 20 dB in both case studies. Therefore, based on the results obtained, it was observed that the addition of dynamic absorbers provided good performance and effectiveness in controlling the first vibration mode of the studied structure.