Observation of bending wave localization and quasi mobility edge in two dimensions

Localization of bending waves is observed on a steel plate decorated with Lucite blocks. A significant experimental feature of the localized modes is an exponential decay of the mode intensity from their peaked centers, with a decay length that increases as (${\mathit{f}}_0$-f${)}^{\mathrm{-}1}$ when the mode frequency f approaches a quasi mobility edge ${\mathit{f}}_0$. Our experimental results, together with finite-element calculations, support the mechanism of strong bending wave scattering by the Lucite block resonances as the source of the localization phenomenon.