Within the framework of the theory of linear piezoelectricity, a study on linear contributions of the total energy release rate in
fracture of the piezoelectric material with a Griffith crack perpendicular to the poling axis was carried out by using the double-torsion technique. The three linear contributions of the total energy release rate due to linear processes are related to the pure mechanical and the electromechanical (or piezoelectric) compliance, and the pure electrical capacitance of the piezoelectric specimen, respectively.
For determination of the contributions, the mechanical and the electromechanical (or piezoelectric) compliances were calculated from
the measured load-displacement curves at each electric field, and the electric capacitance was obtained from the property and
geometric dimension of the sample. In this work, we defined that the pure mechanical compliance and the pure electrical capacitance
are the constant values according to the geometrical size as the intrinsic values without considering the electric effects and the
mechanical effects, respectively, but the piezoelectric compliance is a dependent variable owing to the electromechanical coupling
effects. As the results based on these definition, it was found that the piezoelectric behaviors related to the piezoelectric compliance
aid the fracture of C-82 piezoelectric ceramic irrespective to the direction of electric fields and have more influence on the positive
electric fields, and the total energy release rate, Gtot (=Gm + Gp) in permeable crack model is more effective than the mechanical one,
GM in this research.