Crack kinking in a piezoelectric solid

The intrinsic coupling between the mechanical and the electric _elds assigns a unique feature for the fracture in a piezoelectric solid[ We model the kink of a crack by continuous distribution of edge dislocations and electric dipoles[ The problem admits an approach based on the Stroh formalism[ A set of coupled singular integral equations are derived for the dislocation and electric dipole density functions associated with a kinked crack[ Numerical results indicate that the crack tends to propagate in a straight line under a tensile stress and a positive electric _eld[ For a crack subjected to the mixed mode mechanical loading\ a superimposed positive electric _eld tends to reduce the kink angle[ The in~uence of the non!singular T! stress!charge parallel to a crack is also investigated[ It is shown that a transverse tensile stress or a positive transverse electric _eld will lead to further deviation of the kinked crack from the crack extension line