Modeling and Calculation of Free-flooded Ring Transducers Made of PMN-PT Material

摘要

Underwater acoustic transducers made of PMN-PT material have many advantages compared to those made of PZT material. The lower Young's modulus leads to the lower resonant frequency, the larger electromechanical coupling factor and higher piezoelectric constant provide larger transmitting bandwidth as well as higher transmitting voltage response, etc. In this paper, the theoretical formulae for free-flooded ring transducers are studied, the finite element model of the transducers are also established and solved. The transducers made of PMN-PT and PZT are calculated and compared. The calculated results are consistent with the analytical results. Given a free-flooded ring transducer with the inner radius 0.1m, the thickness 0.01m, and the height 0.2m, the cavity resonance and radial resonance frequency are respectively 1923Hz and 4581Hz when it is made of PZT. However, the frequencies are respectively 1233Hz and 2083Hz when it is made of PMN-PT with the same size. The resonant frequencies are largely reduced. The finite element model gives the similar results. It is also shown that the transmitting voltage response gets larger when the transducer is made of PMN-PT. Free-flooded ring transducers made of PMN-PT are very suitable for sonar applications which require low frequency, small size and high power.