Analysis for the validity of the J-integral for media with voids

It has been shown that for media with voids, the J-integral depends on the integration contour size. To calculate the J-integral for media with voids, a procedure has been proposed for which the J-integral is-independent of t he integration contour size. The J-integral as calculated by the proposed p rocedure is denoted as the J(s)-integral. Constitutive equations for media with voids have been formulated on the basis of an effective stress, as pro posed by Kachanov. It has been shown that the J(s)-integral is independent of the integration contour size both for constitutive equations proposed by the authors and for other constitutive equations, i.e. the models of Gurso n and Rousselier. To verify the proposed formulation for the J(s)-integral, a numerical investigation for media with voids has ben performed.