Failure behavior and failure criterion of conductive cracks (deep notches) in piezoelectric ceramics II: experimental verification

In Part II of this series, we experimentally studied the failure behavior of electrically conductive cracks (deep notches) in poled lead zirconate titanate PZT-8 ceramics. When the critical stress intensity factor was normalized by the critical stress intensity factor under purely mechanical loading and the critical electric intensity factor was normalized by the critical electric intensity factor under purely electric loading, the experimental results revealed that the failure behavior of the conductive cracks in the ceramics was described by an elliptic function of the normalized electric intensity factor versus the normalized stress intensity factor under combined mechanical and electric loading. The experimental results verify the theoretical predictions from the charge-free zone model described in Part I of this series.