On the fracture of paramagnets and soft ferromagnets

Expressions of the energy-release rates are established on the basis of the rotationally invariant (finite-strain) quasi-magnetostatic theory of elastic paramagnets and soft ferromagnets for which neither magnetic ordering nor spin effects need to be introduced. The corresponding path-independent integrals useful in fracture studies are constructed and this is shown to yield essentially the same results as the canonical field-theoretic approach using the notions of Eshelby stress and material forces. A simple application to the antiplane crack problem of a magnetostrictive body in an axial bias magnetic field illustrates the use of the obtained expressions. The same notions could be used to study the so-called magneto-plastic effect. Copyright (C) 1996 Elsevier Science Ltd.