Comparison of continuous and discontinuous constitutive models to simulate concrete behaviour under mixed-mode failure conditions

The paper presents detailed FE simulation results of concrete elements under mixed-mode failure conditions according to the so-called shear-tension test by Nooru-Mohamed, characterized by curved cracks. A continuous and discontinuous numerical two-dimensional approach was used. In order to describe the concrete's behaviour within continuum mechanics, two different constitutive models were used. First, an elasto-plastic model with isotropic hardening and softening was assumed. In a compression regime, a Drucker-Prager criterion with a non-associated flow rule was used. In turn, in a tensile regime, a Rankine criterion with an associated flow rule was adopted. Second, an isotropic damage constitutive model was applied with a single scalar damage parameter and different definitions of the equivalent strain. Both constitutive laws were enriched by a characteristic length of micro-structure to capture properly strain localization. As an alternative approach, the extended finite element method was used. Our results were compared with the experimental ones and with results of other FE simulations reported in the literature. Copyright (c) 2015 John Wiley & Sons, Ltd.