The influence of partial discharge on crack propagation in piezoelectric materials

This paper studies the influence of partial discharge (PD) on crack propagation in piezoelectric materials under combined mechanical and electric loads. According to Stroh formalism, the electric field is obtained based on the semi-permeable electrical boundary condition inside the crack. Then, the crack propagation effects of the electric field without PD are discussed through considering the contribution of the induced electric field inside the deformed crack space to the total energy release rate, and the effect of partial discharge on the crack propagation is also derived under the assumption of the streamer-type mechanism. Finally, the electric field curves and the energy release rate before PD are numerically calculated in the condition of different environments under remote mechanic-electric loads to investigate its effects on crack growth. It is found that the process of partial discharge is very complex and accompanied with randomness in a semi-permeable crack, and the applied mechanical stress, the electric field and dielectric ratio have influence on the crack propagation of piezoelectric materials.