Fracture in Piezoelectric Ceramics and PZT/Electrode Interfaces
The fracture behavior of piezoelectric ceramic (PZT) as well as metal/PZT interfaces under mechanical and electric loading is examined in four and three point bending under conditions of controlled crack growth (see Fig. 1). The experiments are performed in a custom made very stiff testing machine. A special modulation technique, i.e. a small signal compliance method, allows in situ determination of the mechanical compliance Cm, the capacitance Ce, and the piezoelectric compliance Cp as a function of the crack length. By calculating the derivatives of these generalized compliances with respect to the crack surface area we get the total linear energy release rate.