COHESIVE CRACKS VERSUS NONLOCAL MODELS - CLOSING THE GAP

Fracture of quasi-brittle materials. particularly concrete and cement- based material, has been treated in the past using a number of mildly related models. Hillerborg's fictitious crack model (also called cohes ive crack model and Dugdale-Barenblatt model), Bazant's crack band mod el, and nonlocal models, are three of the most used for theoretical as well as for applied analysis. Using a uniaxial formulation and a Rank ine-type model, the present work shows that the cohesive crack may be obtained as a particular case of a fully nonlocal formulation. The dis cussion of the generalization of the uniaxial formulation to triaxial behavior suggests that a directional averaging. rather than an isotrop ic one, may be necessary.