On the efficient implementation of an elastoplastic damage model for large-scale analyses of material failure: a multiscale approach

This paper is concerned with an efficient implementation of material models suitable for the analyses of large-scale engineering problems. Based on the enhanced assumed strain concept (EAS), the final failure kinematics of solids associated with a small-scale are incorporated into the large-scale phenomenological macroscopic constitutive equations. To model the structural response realistically both plastic strains as well as damage-induced stiffness degradation are taken into account. In contrast to the original EAS concept, the parameters defining the enhanced strains are condensed out at the material level. The presented constitutive and numerical framework is applicable to a broad range of different localization phenomena including mode-I, mode-II and mixed-mode material failure. The applicability and the performance of the proposed finite element formulation is investigated by means of a re-analysis of a two-dimensional L-shaped slab as well as by means of a three-dimensional ultimate load analysis of a notched concrete beam subjected to an eccentric load.