This work is concerned with the analytical characterization of the electromechanical
nonlinear effects in the fields surrounding the tip of an interface crack located
between two piezoelectric materials. It is assumed that a prefracture zone arises along
a line segment in front of the crack tip. The prefracture zone is modeled
by electrical displacement reaching a saturation limit and constant stress
distribution. This reduces the problem to a linear interface crack analysis
leading to a Hilbert problem, which is solved exactly. The prefracture zone
length and the stress magnitude in this zone are found from algebraic and
transcendental equations. The latter are derived from the requirement of
stresses and electrical displacement to be finite at the end of prefracture zone
towards the undamaged ligament. Numerical results for certain material
combinations and remote loadings are presented and analyzed. In addition, energy
release rate and crack opening displacements are introduced, which offers the
possibility of formulating a fracture criterion based on the crack opening
displacements.
Keywords
piezoelectric material, nonlinear fracture mechanics,
interface crack, prefracture zone