Fully coupled strain and damage finite element analysis of ductile fracture

The local approach to fracture presented in this paper is based upon the continuum damage theory. The numerical implementation of this theory is made within the framework of the displacement approach of the finite element method. The fully coupled approach used to predict both initiation and propagation is described in detail. To demonstrate the usefulness of this type of local approach, it is applied to the prediction of initiation in an axisymmetrically notched tensile bar subjected to monotonous loading in ductile fracture conditions. The numerical problems arising when propagation of a localized completely damaged zone is modelled are outlined. To overcome these convergence problems, it is proposed to implement a new local fracture criterion together with a new method ensuring a C0 continuity of the damage field throughout the finite element discretized structure. (orig.)