Electric-Field-Induced Crack Initiation From a Notch in a Ferroelectric Ceramic

Crack initiation of ferroelectrics under a cyclic electric field was studied using DCB specimens, which contained through-thickness notches of different lengths. An electric field larger than the coercive field strength of the material was applied and resulted in pop-in of a crack in the direction perpendicular to the field. The length of the pop-in varied with the length of the notch. Finite Element modeling was used to quantify the stresses occurring in the specimen under the application of the electric field. The model took into account the fully coupled ferroelectric and ferroelastic hysteresis behavior. Stress intensity factors were derived from the resulting stress distribution using the weight function method. The results were found to agree well with the experimental data