Two Scale Modelling of Acoustic Waves in Phononic Plates using Homogenization of High-Contrast Media

This paper deals with modeling wave dispersion in periodically heterogeneous plates characterised by high contrasts in elastic coefficients. We study two plate models based on the Reissner-Mindlin (R-M) theory and on the Kirchhoff-Love (K-L) theory. Models of homogenized plates were obtained using the two-scale unfolding method with the high contrast ansatz respected by scaling the elasticity coefficients of compliant inclusions. Consequently, dispersion properties are retained in the limit when the scale of the microstructure tends to zero. For some wavelengths, “mass density” coefficients can be negative, so that intervals of frequencies exist for which there is no propagation of elastic waves, the so-called band-gaps. Dispersion analysis for guided waves is performed for both types of the plates; occurrence of band gaps for the R-M plates is confirmed using numerical examples, however, the homogenized K-L plate model does not admit band gaps.