ECCOMAS Congress 2016 The potential of viscoelasticity for joining band gaps in acoustic metamaterials Miroslawa Lewinska*, Hans van Dommelen, Varvara Kouznetsova, Anastasiia Krushynska, Marc Geers Eindhoven University of Technology Department of Mechanical Engineering P.O. Box 513, 5600 MB Eindhoven, The Netherlands [email protected], [email protected], [email protected], [email protected], [email protected] ABSTRACT Acoustic metamaterials are a novel class of smart materials possessing some unusual properties, uncommon or non-existent in nature. The mechanism of low-frequency elastic wave attenuation based on the local resonance [1], attracts scientific attention not only due to its exotic physics but also because of various potential applications e.g. noise insulation. Since the narrowness of attenuation band gaps in metamaterials is so far the major limitation in terms of possible applications, we investigate the potential of viscoelasticity of the coasting layers of the resonating units for broadening the attenuation frequency range. First, multiple band gaps are obtained in the material with multiple multicoaxial inclusions arranged periodically as was done in [2]. Second, the coating viscosity is used to bridge the closely located band gaps. The introduced concept is verified using the complex dispersion diagrams which are obtained by FEM- calculations based on the Floquet-Bloch theory by means of k(ω) - formulation. The results concerning the wave dispersion are additionally assessed by attenuation diagrams, in which the mitigation of elastic wave propagation is confirmed for the frequencies in between the band gaps in the viscoelastic case. Finally, the transmission spectrum analysis is performed to computationally validate the effectiveness of wave attenuation in the acoustic metamaterial. References [1] Liu, Z., et al. "Locally resonant sonic materials." Science 289.5485 (2000): 1734-1736. [2] Larabi, H., et al. "Multicoaxial cylindrical inclusions in locally resonant phononic crystals." Physical Review E 75.6 (2007): 066601. Powered by TCPDF (www.tcpdf.org) 1 / 1.