Damage process in heterogeneous materials analyzed by a lattice model simulation

Several materials of technological interest could be considered as heterogeneous and their random nature can be accounted to be the cause of the nonlinear behavior. The quantitative evaluation of damage in materials subjected to stress or strain states has great importance due to the critical character of these phenomena, which, at a certain point, may suddenly give rise to catastrophic failure. In previous studies, Carpinteri and his coworkers have presented different aspects of the damage process characterization in heterogeneous materials. Three of these aspects demand our attention: (i) the brittleness number to measure the brittleness level of the structure under investigation; (ii) the fractal dimension in which the damage process develops; and (iii) the global indexes obtained for the Acoustic Emission (AE) analysis. In the present work, a version of the discrete element method formed by bars is used to explore these concepts. A set of quasi-brittle material specimens is simulated and, when it is possible, the numerical results are compared with experimental data. Moreover, a discussion of the obtained results aids to better understand the behavior of this kind of materials, describing the numerical method as a viable tool to extract information from experimental tests on the damage process.