Conducting crack growth in ferroelectric ceramics subjected to electric loading

Crack growth with electrically conducting surfaces in ferroelectric ceramics subjected to purely electric loading is investigated. The boundary of the domain switching zone near the tip of a growing crack under small-scale conditions is determined, based on nonlinear electric theory. The crack tip stress intensity factor induced by domain switching for the conducting crack with growth is numerically obtained. The variation of the electrical fracture toughness obtained from the result of the stress intensity factor is examined for a ferroelectric material with electrical nonlinear behaviour. It is shown that the ferroelectric material can be either toughened or weakened as the crack grows. Steady state crack growth in nonlinear ferroelectric materials is also discussed.