Influence of 1-3 piezocomposite fabrications on lateral modes

Abstract

Properties of 1-3 piezocomposites with periodic structure were characterized. This material can be typically fabricated in using the "dice and fill" method (DFM) and two phases were used (PMN-34.5PT ceramic and epoxy resin). The corresponding numerical simulations allowed to study the influence of spurious lateral modes on electromechanical performance of the thickness mode. This was performed in calculating the bandwidth and the sensitivity of the piezocomposite in water (emission-reception) in the frequency range 1-5 MHz. Moreover, three ceramic volume fractions between 25% and 60% were used. Finally, a comparison of these results with those obtained with a pseudo-periodic 1-3 piezocomposite was made. This composite can be fabricated by a lamination technique (LMT) and the use of a pseudo-periodic structure leads to a minimized effect of the lateral modes (confirmed on the simulated electrical impedance). Thanks to these results an optimum structure was discussed.

Ultrasonic Transceiver with a Regular/Periodic 1-3 Piezocomposite Based on the SAW Resonance Mode on Damping Backing

“…An excitation spike of 300 V amplitude was applied to the transducer structure, so that with an output signal typically 100 mV, it provides nearly −70 dB pulse-echo sensitivity. In the basic characterization, together with the fundamental thickness resonance, typical higher frequency spurious resonances were noticed, related to a lateral Lamb wave in just a piezocomposite plate, with rods filled with epoxy [7][8][9][10][11].…”

“…The general benefits of the 1-3 piezocomposite structure are higher thickness mode piezoactivity (rods with vibration of k 33 -type), lower frequency transverse (planar) unwanted modes, lower acoustical impedance, and transducer Q-factor. Several unwanted higher frequency lateral resonances caused by the regular piezoceramic-epoxy structure in piezocomposites are found and described in References [7][8][9][10][11]. To damp the unwanted resonances, an irregular piezocomposite structure is recommended at this point as in References [12][13][14].…”