Effects of one-dimensional compressive stress on the properties of multilayer piezoelectric ceramic actuator

The mechanical characteristics of the multilayer piezoelectric ceramic actuator (MPCA) are discussed, especially the relation between one-dimensional stress and strain. The samples were rectangular solids made of PZT system ceramics. The polarized samples to which the constant electric field was applied were loaded with one-dimensional stress by a universal testing machine and the displacement was measured. The samples to which the electric field under the coercive field was applied showed a large hysteresis curve when one-dimensional stress up to 3.3*10/sup 7/ N/m/sup 2/ was loaded and removed. The samples to which no electric field was applied showed the reduction of the length equivalent to their residual displacement after the one-dimensional stress of 6.6*10/sup 7/ N/m/sup 2/ was loaded and removed. The hysteresis curve became smaller when the electric field over the coercive field was applied to the samples. Permittivity, dielectric loss, and electromechanical coupling factor were measured.<
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