Identification of lateral vibration modes of piezoelectric composites 1-3 and their effects

Piezocomposites polymer-ceramic 1-3 show high potential for use in many applications. Besides the existence of thickness and planar modes, they have lateral modes due to ceramic rod´s periodicity, which affects its efficiency. Piezocomposites 1-3 (polyurethane-PZT) were prepared with ceramic concentrations varying between 11 and 42 vol %. All the samples disk with 27 mm in diameter, contained the same ceramic rod geometry. The electric impedance spectrum of airbacked piezocomposite was determined, the vibrational modes perturb the behavior of the spectrum and modify the thickness resonant mode. These perturbations were detected in emission and reception of acousto-electric spectra. The dependence of lateral modes frequencies with ceramic´s rod periodicity was determined. As happens with thickness mode, the coincidence between emission and electric resonance frequencies and between reception resonance and electric antiresonance frequencies of the lateral modes was highly remarkable. The radiation pattern profile was also measured to identify the effects of these lateral modes