Issue 30

A. Fernández-Canteli et al., Frattura ed Integrità Strutturale, 30 (2014) 383-393; DOI: 10.3221/IGF-ESIS.30.46 386 E : Young’s modulus [MPa], ν : Poisson coefficient [-], f c : compressive strength of the concrete [MPa] and f t : tensile strength of the concrete [MPa]. Figure 3 : Specimen set up into the servohydraulic MTS Bionix 25 kN machine. E [MPa] ν [-] f c [MPa] f t [MPa] Steel 210000 0.3 - - Concrete 33010 0.2 31.45 2.665 Table 2 : Mechanical input parameters for the material used in the ATENA and ABAQUS calculations. In order to propitiate the factual non-symmetry behavior of the crack initiation at the notch and further propagation in the real specimen due to the non-uniformity of the aggregate, symmetry is disregarded so that the whole specimen is considered in the computations. 2D-Model 1 using ATENA code An adaptation from the model of Holušová et al. [19] is performed for the new dimensions adopted as presented in Tab. 1, using the same commercial software ATENA 2D. The material is identified in ATENA as the model for concrete 3D Non Linear Cementitious 2 working under plain stress or plain strain conditions and SBETA that works only under plain strain condition, see [20,21]. Steel bars are there modeled as ideal lines, which simulate the pulling load axis of the testing machine. The mesh and boundary conditions are shown in Fig. 4. The size of elements is, typically, 2 mm with a refinement up to 1 mm around the starting notch. 2D-Model 2 using ABAQUS code with rigid bars This model, created in ABAQUS, is based on the same premises as model 1, i.e. assuming the bars maintain a fixed pulling axis orientation during the test. This implies impeding any deviation or relative transversal displacement of the bars that unavoidably occurs during the real test as a consequence of the necessary compatibility between displacements of