A J-INTEGRAL FOR THE ANALYSIS OF ELECTRICALLY INDUCED MECHANICAL-STRESS AT CRACKS IN ELASTIC DIELECTRICS

A path independent J-integral is formulated for the problem of a crack in an eiastically deformable dielectric subject to electrostatic and mechanical load. The result is essentially the invariant Γ-integral of Cherepanov [Mechanics of Brittle Fracture, McGraw-Hill (1979)], but it accounts specifically for large deformations. The integral can be used to obtain a result for the mechanical stress intensity factor at the tip of a conducting crack in the dielectric in the presence of an electrical field. This has implications for the mechanical stresses that would be present when a dielectric containing such cracks experiences insulator failure at high electric field levels. Such stresses may cause this failure. © 1990.