J-integral for ferroelectric compact-tension specimens with electric field

摘要

Experiments based on the compact tension geometry are applied to a relaxer composition of lead lanthanum zirconate titanate. This composition is transparent, and displays electro-optical and piezo-optical coupling. A standard photo-stress arrangement gives a direct view of electric field and stress concentrations. Electric field is observed to cause cracks to close. This is consistent with earlier predictions of a negative energy release rate.