Low-frequency band gaps in Y-type phononic crystals

Abstract

In this paper, an Y-type of locally resonant phononic crystal (LRPC) material model is analyzed in detail. Some geometric parameters of the material model are investigated using FEM to assess the trends of band gaps (BGs). The BGs results show that the material model can open a low-frequency BG less than 200 Hz. When the lattice constant of the material model cell is determined, the geometrical parameters of scatterers are found to be the key to open BGs. The results show that the effect of the scatterer on BGs is studied by adjusting the two ratios (the ratio of the square bottom edge length to height of the scatterer composed of lead and the ratio of the square bottom edge length to height of the scatterer composed of aluminium), respectively. The changes of the two ratios have little effect on the upper edge of BGs. Similarly, the change of the ratio of the scatterer composed of aluminum has little effect on the lower edge of BGs. However, the variation of the ratio of the scatterer composed of lead can make the lower edge of BGs lower and increase BGs width. The vibration and noise reduction devices with different working frequencies can be designed by adjusting the geometric parameters of the scatterer.