Effect of electrostatic tractions on the fracture behavior of a dielectric material under mechanical and/or electric loading

The effect of electrostatic tractions on the fracture behavior of a dielectric material under mechanical and/or electric loading is analyzed, by studying a pre-cracked parallel-plate capacitor, and illustrated by plots. The results indicate that electrostatic tractions on the electrodes compress the material in front of the crack tip, while electrostatic tractions on the crack faces have the tendency to close the crack and stretch the material behind the crack tip. Mechanical load is the driving force to propagate the crack, while applied electric field retards crack propagation due to the electrostatic tractions. As a direct consequence, the fracture criterion is composed of two parts: the energy release rate must exceed a critical value and the mechanical load must be higher than the critical value for crack opening.