Geometric effects on the stopband structure of 2-2 piezoelectric composite plates

Piezoelectric composites have become an important part of medical transducer design over the past several years. A critical issue in the proper design of these materials is an understanding of the stopband edge resonances which produce a net piezoelectric response. Previous work has been done showing the stopband structure for 2-2 composite plates which have a unit cell length greater than the plate thickness ( d>t). A simple model for predicting the stopband resonance frequencies in 2-2 composite plates with the length of the unit cell smaller than the plate thickness (d<t) is given, and experimental data which strongly support the model are presented. The data are compared to previous results and differences are discussed in the light of the symmetries required to produce piezoelectric coupling and Lamb wave behavior at different regions of the Lamb dispersion curves