ELECTROELASTICITY EQUATIONS AND ENERGY APPROACHES TO FRACTURE

Different formulations of the electroelasticity theory are compared fr om the point of view of their consequences to fracture problems. In th e quasielectrostatic approximation. for elastic dielectrics, the local equations of these models are equivalent. but their global forms are different as a result of different decompositions of the force of elec tric origin into surface and volume contributions. Three versions of g lobal balance laws are considered, corresponding to the representation of the electric field action as surface forces, volume forces or comb ined surface and volume forces. The purpose of the paper is to make a choice between these models in the context of the Griffith theory of f racture. A particular fracture problem is investigated and it is prove d that the models in which volume forces of electric origin are suppos ed are not able to give a rational description of the considered physi cal situation. The only reasonable formulation in this case is that as suming an action through contact for the electric field. (C) 1997 Else vier Science Ltd.