Quasi-static straight and oscillatory crack propagation in ferroelectric ceramics due to moving electric field: experiments and theory Original Research Article

A novel experimental setup was developed which allows controlled quasi-static crack propagation in initially unpoled ferroelectric ceramics as a result of a moving electric field. Applying an electric field on unpoled specimens partially covered with electrodes induces mechanical stresses that drive crack propagation. Different crack morphologies from single straight and oscillating crack propagation to straight double crack propagation were observed. The load for the transition from straight to oscillating crack propagation as well as the wave length for the oscillating crack are determined and compared with bifurcation theory. The experimental results are in good agreement with theoretical predictions. Comparing static with quasi-static experiments, the observed crack lengths were significantly smaller in the latter case. This behavior is attributed to the time dependency of domain switching.