Proposição, avaliação numérica e experimental de um absorvedor dinâmico de vibrações multimodal

Abstract

Dynamic Vibration Absorbers (DVA) have been widely used for passive control of structural vibrations. In their simplest configurations, those devices have their mitigation capacity confined to narrow frequency bands, which limits, to a large extent, their practical effectiveness. In this work, it is proposed a methodology for the optimal design of a multimodal dynamic vibration absorber, intended to attenuate the amplitude levels around various resonance peaks simultaneously. The particular configuration considered is formed by blades containing circular disks in their tips. The optimization is performed taking into account design constraints. Moreover, the variability inherent to the construction of the base structure and of the DVA itself is considered aiming at obtaining robust designs in future studies. A technique for substructure coupling based on frequency response functions (FRFs) is used to evaluate the dynamic behavior of the coupled structure (base structure + DVA), given the FRFs of each substructure separately. The use of this technique enables the design of the DVA and the evaluation of its performance based solely on the use of experimental FRFs of the base structure, which makes numerical models unnecessary. Monte Carlo simulation is used to evaluate the influence of the uncertainties on the effectiveness of the multimodal DVA. The procedure is illustrated by numerical and experimental results obtained for a rectangular plate and hermetic compressor housing.