Propagation of a semi-infinite conducting crack in piezoelectric materials: Mode-I problem

In this paper, the mode-I transient response of a semi-infinite conducting crack propagating in a piezoelectric material with hexagonal symmetry under normal impact loading is investigated. The integral transform methods together with the Wiener-Hopf technique are used to solve the mixed boundary value problem under consideration. The solutions of the coupled fields are derived for two cases, i.e., generalized Rayleigh wave exists or not. The dynamic stress intensity factor and dynamic electric displacement intensity factor as well as their universal functions are obtained in a closed form. The numerical results for two universal functions are provided to illustrate the characteristics of dynamic crack propagation. It is found that the universal functions for the dynamic stress and electric displacement intensity factors vanish when the crack propagation speed reaches the generalized Rayleigh speed which is the propagation speed of surface wave in a piezoelectric half-space with metallized surface. It is noted that the electromechanical coupling coefficient has an important influence on the dynamic fracture characteristics.