4G-1 A Fast Algorithm for Calculating Band Structures in Two-Dimensional Phononic-Crystal Plates

Based on Mindlin´s plate theory and the plane wave expansion method, a formulation is proposed to study the propagation of Lamb waves in two-dimensional phononic-crystal plates. The method is applied to calculate the frequency band structure of Lamb waves in phononic-crystal plates composed of crystalline nickel cylinders in an epoxy matrix with finite thickness. It is found that absolute band gaps for Lamb waves between different pass bands are opened up. The influence of filling fraction and plate thickness on the absolute frequency band gap width is calculated and discussed as well. Finally, we note that the proposed method provides a concise and efficient way in analyzing the band structures of thin phononic-crystal plates in lower bands