Dynamic behavior of a ferroelectric actuator

The authors study the effect of polarization switching on the dynamic behav ior of a model ferroelectric actuator using the system dynamics approach. T he analysis indicates that the stress resulting from polarization switching always oscillates at a frequency slightly lower than the system resonance frequency if the applied electric field is harmonic and is of a frequency l ower than one-half of the system resonance frequency, and that the oscillat ing frequency is determined by the intrinsic properties of the system. In t he case that the frequency of the applied electric field is larger than one -half of the system resonance frequency, the stress oscillates at twice the frequency of the applied electric field. Furthermore, the oscillating stre ss resulting from polarization switching has a larger amplitude than the st ress occurring in the absence of polarization switching. The authors relate these results to the experimental observations that the fatigue life of fe rroelectric ceramics is shortened substantially when polarization switching takes place.