Improvement of the Effective Parameters of 1-3 Piezocomposite Using Multi-Layer Polymer and PMN-PT Relaxor Single Crystal

In this study, 1-3 piezocomposite with multi-layer polymer based on PZT piezoceramics and PMN-0.33PT relaxor single crystal was modeled and analyzed, and the obtained results were assessed. Recently, PMN-PT relaxor single crystals have been introduced as a suitable alternative to the PZTs due to their great piezoelectric coefficients. In addition, use of multi-layer polymers made from a combination of a polymer with a high stiffness coefficient for maintaining strength and a polymer with a much lower stiffness coefficient for increasing the electromechanical coupling coefficient improved the parameters of 1-3 piezocomposite. In addition, 1-3 piezocomposite with a multi-layer polymer based on PMT-PT increased the electromechanical coupling coefficient as well as the bandwidth of the filling fraction with the maximum value of kt. This finding facilitated producing a piezocomposite at low filling fractions with very high kt and very low characteristic acoustic impedance close to the characteristic impedance of the environment. It was shown that in the case where 75 % of the volume of the polymer phase was composed of silicone rubber, 1-3 piezocomposite with multi-layer polymer based on PMN-0.33PT single crystal could increase the electromechanical coupling coefficient to values greater than 0.95. In addition, in this case, it is possible to achieve a coupling coefficient of 0.94 and a characteristic impedance of 7 MRayl at the filling fraction of 0.2. The obtained results were analytically confirmed through the finite element numerical results.