Piezoelectric constants measured from converse piezoelectric effect and piezoelectric ceramic actuators

The piezoelectric constants d33 and d31 under weak and stronger field were measured from strain S vs electric field E curves for the converse piezoelectric effect. It was shown that on the curves there is a critical field Eb, from which strains and d33, d31 were obviously increased, and the result was discussed in the view of reorientation of 90�� domain intrinsically existed in piezoelectric ceramics. This method of measuring d33, d31 is simple and convenient, as well as more practical, especially for piezoelectric ceramic actuator, as compared with that usually obtained them from positive piezoelectric effect.