Piezoelectric and Electrostrictive Materials for Transducers Applications. Volume 1
Final rept. 1 Feb 1991-31 Jan 1992,
PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
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Highlights of the past years activities include An increased emphasis upon the flextensional moonie type actuators, modeling both the internal stress distribution as a function of geometry, and the very interesting resonant mode structure of the composites A more refined focus upon the performance of piezoelectric ceramic transducers, particularly under high drive levels is developing with concern for the extrinsic domain and phase boundary contributions to response. Measurement and modelling are being used to explore the nonlinearity and the frequency response and to examine the phase partitioning at the rhombohedral tetragonal morphotropic phase boundary in the PZT system. Phenomena limiting lifetime in polarization and phase switching actuators are being explored to separate surface and volume effects and those due to grain size and flaw population differences. New work has been initiated to examine Acoustic Emission as a technique, in combination with Barkhausen current pulse analysis, to separate and evaluate domain switching and microcracking in polarization switching systems.
- Electricity and Magnetism