Fatigue crack growth in ferroelectrics under cyclic electrical loading

Fatigue crack growth experiments with DCB specimens made of PZT subjected to cyclic electrical and constant mechanical loading are evaluated from the fracture mechanical point of view. Therefore, correlations have been developed from numerical simulations with the Finite Element Method providing the electric displacement intensity factor K-IV which depends on crack length and electromechanical loading conditions. The simulations account for limited permeable crack faces and explain the observation of a dielectric crack closure effect. Fatigue crack growth is then described by a power law. To simulate ferroelectric domain switching, a numerical micromechanical model has been developed. Finite Element calculations shed light on the physical mechanisms of crack growth due to electric cycling.