The Influence of the Filling Factor on the Formation of Local Resonance Regions in a Two-Dimensional Phononic Hexagonal Structure

The paper presents the influence of the fill factor of the elementary cell of a quasi-two-dimensional phononic structure with a hexagonal arrangement. The propagation of a mechanical wave in the structure was studied in the range of selected acoustic frequencies using the finite difference algorithm in the time domain. As a result of multiple reflections of the mechanical wave, as well as the occurring diffraction and interference phenomena, local resonance areas are created inside the structure, which have a significant impact on the occurrence of the phononic band gap phenomenon, i.e., such frequency bands for which the wave does not propagate in the structure. In addition, local resonance areas reduce the transmission speed of the mechanical wave front in the phononic structure.