No abstract

Analytical models can be useful tools to develop efficient transducers dedicated to a specific application field. This work proposes a homogenization technique for establishing the effective coefficients and parameters of 1-3 piezocomposite whose both phases are piezoelectrically active. Such piezocomposite materials may have homogenized electromechanical properties resulting from positive hybrid effect. A numerical simulation of the effective parameters resulting from a PZT-5A / PVDF-TrFE composition shows that, volume fraction influences significantly on the properties of the piezocomposite and consequently on its behavior in service. As an end-user application for ultrasound imaging, those piezocomposite materials are effectively integrated in a piezocomposite transducer, coupled with a dedicated backing. The resulting characteristics in terms of impulse response and associated electroacoustic echo are compared and discussed for typical configurations. A method for the optimization of the design of such piezocomposite transducer is presented. Specific estimators based on the bandwidth flatness BWF and bandwidth amplitude product BWA are proposed as stable and smooth criteria for an optimization procedure.

The homogenization of piezocomposites is a research challenge as the development of analytical models remains a challenge. In this perspective, this work contributes to the development of an analytical model to predict the thermoelectromechanical behavior of the 2-2 piezocomposite where both phases are electrically active. To establish this model the series/parallel method was used and thus the effective homogenised properties of the composite are established. The influence of the volume fraction on the characteristic parameters was studied and found that a numerical simulation of the effective parameters resulting from a {PZT-5A/PVDF-TrFE} composition shows that, volume fraction influences significantly on the properties of the piezocomposite and consequently on its behavior in service. Due to the unavailability of experimental data in the literature, the validation of the model is done with reference to the model applied to the 1-3 piezocomposite. Therefore, to a certain extent, it is found that the results are in agreement. Based on the results of this model and in comparison with those formulated from 1-3 piezocomposite as presented in the paper, the studied 2-2 piezocomposite could be used where 1-3 piezocomposite is sometimes integrated, as the highest performance piezocomposite. However, this remains to be validated experimentally for targeted applications to be useful for the scientific and even industrial communities.