THE INTERACTION BETWEEN CRACK AND ELECTRIC DIPOLE OF PIEZOELECTRICITY

摘要

Discrete dipoles located near the crack tip play an important role in nonlinear electric field induced fracture of piezoelectric ceramics. A physico-mathematical model of dipole is constructed of two gen- eralized concentrated piezoelectric forces with equal density and opposite sign. The interaction between crack and electric dipole in piezoelectricity is analyzed. The closed form solutions, including those for stress and electric displacement, crack opening displacement and electric potential, are obtained. The function of pi- ezoelectric anisotropic direction, p_α(θ)=cosθ+p_αsinθ, can be used to express the influence of a dipole's direction. In the case that a dipole locates near crack tip, the piezoelectric stress intensity factor is a power function with -3/2 index of the distance between dipole and crack tip.