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MECSOL 2022
8th International Symposium on Solid Mechanics
Parametric analysis of quasi-periodic metastructures with damped local resonators
Submission Author:
Marcelo A. Trindade , SP
Co-Authors:
Matheus Prado, Marcelo A. Trindade
Presenter: Marcelo A. Trindade
doi://10.26678/ABCM.MECSOL2022.MSL22-0213
Abstract
Metastructures or (quasi-)periodic structures have several applications such as vibration, acoustic and vibroacoustic attenuation, acoustic absorption and insulation, vibration and shock mitigation, wave propagation control and focusing, among others. They are inspired by phononic crystals that exhibit bandgaps, that are frequency ranges where elastic or acoustic waves cannot propagate. These bandgaps can be obtained in (quasi-)periodic structures either due to their periodicity that may lead to the Bragg scattering phenomena or by adding local resonators distributed along the host structure, that act as vibration absorbers. In the first case, the bandgaps depend on a relation between the frequency range of interest and the periodicity properties of the structure. In the second case, the bandgaps depend on the properties of the local resonators and their distribution. These two types of bandgaps may also be combined in some cases. For typical engineering structures, such as beam or plate-type structures, the introduction of Bragg scattering bandgaps generally requires substantial structural modification and may only be effective in terms of vibration mitigation for medium-higher frequency ranges. On the other hand, bandgaps due to local resonances may also be designed to be effective in the lower frequency range. Both bandgaps types, however, depend on a number of design variables and constraints. Moreover, the addition of local resonators to the host structure also allows to increase its damping properties leading to another potentially effective way to reduce or mitigate undesired vibrations. Therefore, this research effort can be easily related to the search for solutions considering distributed low-size mechanical vibration absorbers added to low-weight flexible structures that has attracted numerous research groups. The main novelty of the concept of metastructures with local resonances is the fact that the periodicity of the host structure and/or of the local resonators distribution may add to the overall performance. The main objective of the proposed work is to present recent results and analyses on the addition of periodic and/or quasi-periodic local resonators to beam- and plate-type structures, including an assessment of the effects of the parameters of the local resonators and of their distributions on the host structures on the vibration mitigation performance in the lower frequency ranges. Results indicate that added mass constraints tend to restrict satisfactory performances to narrow frequency ranges and, for that reason, the effective damping potentially added by the local resonators are essential to provide satisfactory performances over a wider frequency range. For the same reason, it is also shown to be essential to analyze distributions of different resonator types that are tuned to different target resonance frequencies in order to provide a multimodal or broadband vibration mitigation solution.
Keywords
metastructures, (quasi-)periodic structures, Vibration control
