Mechanical Strength Simulation of Concrete Samples Using COMSOL Multiphysics ® Software with 3 D Mesh Generated By Industrial Tomography System

Analysis of concrete structures is usually carry out by destructive methods. The internal volume flaws directly influence the concrete properties. Such inclusions are empty or even resulting from manufacture process or degradation by percolation leaching, dissolution and chemical reactions between its constituent. Industrial tomography system (ITS), has proven to be a powerful tool for analyzing and determining the internal volume of the objects. In this context, this work aims to show that it is possible to generate representative triangular meshes from real samples of concrete from data obtained with 3D ITS and use them to simulate mechanical properties. The results of these simulations can be used to compare them with the results of mechanical strength obtained in the laboratory. Thus, the acquisition of 3D tomography of a sample of concrete cylindrical with dimensions of 10 cm by 5 cm diameter using the ITS from Institutos Lactec in Curitiba (Figure 1) was performed. Then, data preprocessing was carried out from STL data scanner software in MeshLab Open Software (Figure 2). The preprocessing was required to reduce the set of data that make possible the simulation, but without losing the mechanical and morphological properties of the concrete sample. The studies were applied to COMSOL Multiphysics® software equivalent to laboratory compression tests of concrete samples. These samples have, in addition to concrete, aggregates and as rock and sand are taken from varying depths, with different states of compression, so that when tested to provide information on the state of the dam. Simulation consisted in keeping the base fixed of sample cylindrical and apply compressive force distributed over the entire area of the top of the cylinder. This happens until there is a rupture of the sample. In actual tests, it is possible see that the breaks occur in regions of interface between concrete and aggregate, indicating that these are the weakest points of the sample. In mechanical simulations using COMSOL was possible to verify that the interface regions have higher concentrations of stress (Figure 3). Figures 3 and 4 show the results obtained for the concrete sample studied. Due to limitations in computational cost, it was possible to reduce the number of granites. In this work only cement and 4 granite was defined to simulation. Figure 3 shows the distortion map due to the applied load and the distribution of stresses applied to the sample. The computer simulation of the concrete behavior subjected to mechanical stress enables the prediction of catastrophic events in the dams, reducing laboratory costs and reducing the time trials. The results obtained here are not definitive, but may be the considered for future studies if performed procedures with mesh data from 3D tomography and simulation using finite elements that allow process all sample data and compare them with mechanical tests laboratory.