Applicability of crack energy density to fracture strength evaluation of piezoelectric ceramics

A lot of studies have been made to grasp and describe fracture behavior of piezoelectric material under electromechanical loadings. However, even the criterion to describe the dependence of static fracture strength on electric field has not been established yet. In this paper, a fracture criterion based on mechanical contribution of crack energy density is proposed and its applicability is studied by analyzing not only the three-point bending fracture test results by the authors on piezoelectric ceramics called C-2 but also the compact tension fracture tests by Park and Sun on piezoelectric ceramics called PZT-4, based on the criterion.