7F-2 Analysis of Lamb-Wave Dispersion and Band Gaps of Two-Dimensional Piezoelectric Phononic-Crystal Plates

Based on Mindlin's piezoelectric plate theory and the plane wave expansion (PWE) method, an eigen-matrix is formulated to study the frequency band gaps and dispersion relations of the lower-order Lamb waves in two-dimensional (2D) piezoelectric phononic plates. The phononic plates analyzed are composed of solid-solid and air-solid constituents with square and/or triangular lattices. Factors that influence the opening and width of the complete band gaps of Lamb waves are identified and discussed. For solid/solid phononic plates, the filling material chosen with a larger mass density, proper stiffness, and weak anisotropic factor embedded in a soft background material is suggested to obtain wider complete band gaps in the lower bands. On the other hand, for air/solid phononic plates, to achieve the complete band gaps are relatively difficult, and the background material itself with a proper anisotropy and a high filling fraction of air holes may favor the band-gap formation.