Vibration characteristics of piezoelectric discs with elastic additions

Finite element method and modal analysis technique have been used to predict the vibration characteristics of piezoelectric discs, and discs with elastic additions. The predicted results show that for discs with elastic additions, the number of modes in the frequency range of interest are increasing greatly, and amplitudes are reduced when modes are coupled to each other. The modes which are most strongly excited are still those thickness extensional modes of the discs alone, however their surface motions have shown characteristics usually seen in discs with large D/T ratios. The electrical impedance responses of the discs were measured and have shown very good agreement with those predicted by FE analysis. The results are discussed with respect to understanding and further modeling of the backing of the piezoelectric transducer.