Experimental analysis and truss-like discrete element model simulation of concrete specimens under uniaxial compression

In this work, the Acoustic Emission signals were captured by sensors applied to the external surfaces of a prismatic concrete specimen subjected to compression loads. In this context, the experimental results are presented in terms of stress-time diagram and also, the variation in the Gutenberg-Richter law, that is, the relation proposed between the Acoustic Emission cumulative counts and its magnitude. This law is obtained during each phase of the test and in the final stage. A three-dimensional lattice model, known as truss-like Discrete Element Method, also modeled the same specimen. The numerical results present a good correlation with those obtained from the experimental test also in terms of typical Acoustic Emission parameters, such as count rate, cumulative counts, and the variation in the Gutenberg-Richter law. Using the truss-like discrete element model, the relationship between the Acoustic Emission signal magnitude and the energy released from each localized rupture has also been analyzed. The obtained results are compatible with the Gutenberg-Richter energy-magnitude relation. Finally, the numerical results have been analyzed in terms of Acoustic Emission signal frequency. The simulation presents the same pattern with the experimental results: a shift towards lower Acoustic Emission signal frequencies during the evolution of the damage process. (C) 2013 Elsevier Ltd. All rights reserved.