Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
INVESTIGATION OF DAMPING EFFECTS IN MONOCOUPLED PHONONIC CRYSTALS AND METAMATERIALS
Submission Author:
Emanuel Victor Borges de Morais Cruvinel , SP , Brazil
Co-Authors:
Emanuel Victor Borges de Morais Cruvinel, Romes Antônio Borges, Domingos Rade
Presenter: Emanuel Victor Borges de Morais Cruvinel
doi://10.26678/ABCM.COBEM2021.COB2021-2229
Abstract
Periodic structures are composed of identical substructures or cells that are connected end to end in a similar manner, with their periodicity characterized by geometrical or material discontinuity. Due to their periodicity, these structures present special dynamic characteristics, acting as a mechanical filter for elastic waves propagating in specific frequency intervals, known as stop bands or band gaps. The large majority of previous investigations disregard energy dissipation effects. However, real structures dissipate energy by various mechanisms when they vibrate, for instance, due to friction at connections, opening and closing of material microcracks or internal material friction when deformed. Energy dissipation, also known as vibration damping, can alter frequency band structures, thus modifying the behavior of wave propagation. The purpose of this paper is to analyze the effect of damping on elastic waves attenuation of periodic structures when subjected to forced harmonic excitation. The equivalent viscous model damping applied to four different configurations of periodic structures, with and without internal resonators, modeled as lumped mass-spring-damper subsystems is investigated. For each configuration, the equations of motion of the unit cell are derived, and the transfer matrix method is implemented to model the elastic wave propagation along the periodic structure and to obtain the propagation constant that allows the construction of dispersion curves. Different levels of damping are considered, and their effects in pass bands, stop bands and frequency response functions are analyzed.
Keywords
periodic structures, stop bands, band gaps, damping, acoustic metamaterials
