KEYWORDS: Polarization, Switching, Dielectric polarization, Ferroelectric materials, Data modeling, Dielectrics, Ceramics, Silver, Actuators, Control systems
In this experimental work, multi-axial, non-proportional polarization rotation tests were performed for a commercial soft PZT material under purely electric field loading. Large pre-poled piezoceramic plates were cut into rectangular blocks of size 15mm × 5mm × 5 mm, with their long axes inclined at a set of angles (from 0° to 180°, in steps of 15°) to the initial poling direction. After cutting, the top and bottom 5mm × 5 mm surfaces were electroded with a thin layer of silver paint and then, a ramp-shaped electric field was applied to cause the polarization to change. In addition to the polarization measurement along the field loading direction, the normal strain responses in all three coordinate directions were monitored simultaneously using strain gauge technique. Based on a series of polarization and strain versus electric field curves, switching (domain reorientation threshold) surfaces were constructed in the bi-axial electric field plane using the conventional offset method. The experimental data can be used to examine the existing switching criteria in phenomenological models for the non-linear constitutive behavior of piezoceramics.
Modern piezoelectric transducers normally have complicated structures and work under severe loading conditions. Application of an external load in excess of a critical level will cause domain switching in the material and therefore lead to a significant nonlinearity and hysteresis in the polarization and strain response. To develop a constitutive model concerning the large-signal nonlinear behavior of ferroelectric piezoceramics, it is desirable to determine a switching criterion in the multiaxial stress and electric field states.
In this experimental work, "soft" lead zirconate titanate (PZT) specimens in initially unpoled state were subjected to a proportional electromechanical loading, in which a compressive stress and a parallel, proportional electric field were applied simultaneously. By varying the relative proportions of the stress and E-field between tests, a family of nonlinear polarization and strain responses were obtained. An attempt has been made to explain the experimental findings by simultaneously taking into account the contributions of dielectric response, elastic deformation, piezoeffects, and irreversible domain switching. Based on an offset method, switching (domain reorientation threshold) surfaces were mapped out in the biaxial stress and electric field space. Finally, several switching conditions existing in the literature were summarized and compared with the experimental data obtained in this work.
Polarization and longitudinal strain of the commercial soft PZT piezoceramic PIC151 were measured as a function of amplitude and frequency of an AC electric field. The range of frequencies considered was selected in the quasi-static range from 0.01Hz to 1.0 Hz. The electric field was selected as triangular loading. Besides the standard hysteresis loops for polarization (P) and strain (S) versus electric field (E), strain versus polarization curves (S-P curves) were plotted in separate diagrams. It was shown that both polarization and strain were frequency dependent. The coercive field increased with the loading frequency. Furthermore, a significant hysteresis was observed for S-P curves at a loading frequency below 1Hz. At a frequency of 1Hz, however, the S-P plots were nearly close to an idealized parabolic curve without hysteresis. A tentative explanation shall be given for these observations in terms of the rate effects of the domain switching process.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.