PSI - Issue 66

Jonathan Duarte Oliveira et al. / Procedia Structural Integrity 66 (2024) 313–319 Author name / Structural Integrity Procedia 00 (2025) 000 – 000

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Each test is recorded by a 30 frames per second camera, in order to perform an image correlation analysis by using the GOM software (GOM GmbH, 2019). It is interesting to highlight that, due to the irregular surface characterizing the pervious concrete, no surface preparation is needed. Ten specimens are tested at 28 days of curing and the compressive strength is. An example of the typical failure experimentally observed is shown in Figure 2(b). The average compressive strength is equal to 4.80 ± 0.51 MPa. Figure 2(c) shows a typical image used for crack path analysis by GOM. The obtained value for the average compressive strength falls in the range provided by the American Concrete Institute (ACI (2010)), that is from 2.8 to 28 MPa. The low value of the compressive strength here obtained is due to the fact that the aggregate used has a very lamellar shape and it is brittle. 3. Numerical Simulations 3.1. The Lattice Discrete Element Method The formulation of the Lattice Discrete Element Method (LDEM), proposed by Riera (1984), is extensively explained in several works available in the literature such as, for example, Iturrioz et al. (2009), Kosteski et al. (2012), Puglia et al. (2019). Such a Method schematizes a continuum medium by means of a 3D lattice. The 3D lattice is formed by the repetition of the basic cubic module shown in Figure 3a. The basic cubic module, with a side equal to , is composed by 26 truss elements and 9 nodes, being the masses concentrated at nodes and distinguishing the longitudinal from the diagonal elements, depending on their length (Fig. 3a). Each node has three degrees of freedom, representing the three components of the displacement vector in the global reference system x,y,z. The LDEM formulation can be implemented in the Abaqus/Explicit environment. In this scenario, a wide range of numerical problems can be solved, as reported in Silva et al. (2020), Vidal et al. (2020) and Kosteski et al. (2024). Moreover, also an LDEM-FEM formulation has been developed (Silva et al., 2020; Kosteski et al., 2024), where the LDEM is used to model the regions characterised by cracks, whereas the FEM is used elsewhere.

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Fig. 3. (a) Basic cubic module used in the LDEM; (b) LDEM model of the specimen under compression (where u y is the displacement in y direction).

3.2. Model description A three-dimensional model is built to simulate the mechanical behaviour of the examined material under compression by using the LDEM formulation implemented in the Abaqus/Explicit environment (Fig. 3(b)). The size of the basic cubic module is equal to L =10 mm, whereas the sizes of the whole model correspond to the nominal ones of the specimens. The applied boundary conditions are shown in Figure 3(b). The input data are listed in Table 1, where  is the material density, E is the elastic modulus, G f is the energy release rate and  p is the critical strain. A random field, with a Weibull distribution, is implemented for the energy release rate in order to simulate the concrete heterogeneity.