The influence of Maxwell stresses on a moving crack in piezoelectric materials

A plane problem of a moving crack with constant velocity in piezoelectric materials is investigated systematically. Based on the extended Stroh formalism, the closed-form expression of electric displacement in the moving crack, the electrostatic fields and dynamic stress and dynamic electric intensity factors are obtained in a concise form. The influence of Maxwell stresses and the speed of the crack is studied when the model bears combined mechanical and electrical loads at infinity. The electrically semi-permeable crack boundary condition is adopted. The effects of mediums inside the crack and surrounding the matrix at infinity are also analyzed theoretically. Numerical results are presented and it is found that the dynamic intensity factors are related not only to the electric field, but also to the velocity of the moving crack.