Shielding stresses for soft PZT

Crack opening displacements (COD) were obtained on fully developed cracks in compact tension specimens manufactured from a commercial, soft lead zirconate titanate (PZT). The data were evaluated using the weight function method to provide crack closures stresses as a function of distance to the crack tip. As ferroelastic toughening in PZT shows time-dependent effects, data were taken at different stages of unloading. The peak closure stress was determined as 20MPa