High temperature and corrosive environments in which castable refractories are utilized involve high risks. In this context, the characterization of their fracture properties becomes extremely important, and an essential tool for the correct selection, application, development and research of these materials. However, crack propagation features depend on the underlying microstructure and heterogeneity, thereby creating a Fracture Process Zone (FPZ), i.e., an energy dissipating region near the crack tip. If crack propagation is studied with surface data alone, much information from the fracture process in the bulk is not available. In this internship project, it is proposed to obtain insight about the FPZ using volumetric data acquired via in-situ Wedge Splitting Tests (WSTs) performed in an X-ray scanner. The displacement field will be experimentally measured with Digital Volume Correlation and will be used as boundary conditions to drive finite element simulations. The measured displacement field will also be confronted to the simulated kinematics to check its validity. Relevant mechanical parameters will be extracted as the minimizers of the chi-squared norm of the difference between measured and simulated data (i.e., load and displacement fields). This methodology will be used to obtain parameters that match as best as possible the experimental results with computer simulations. The FPZ would then be measurable from damaged elements, and computer simulations would consider the wake effects given by energy dissipation mechanisms (e.g., mechanical union of aggregates after cracking, crack branching and microcracking). This information will also give insight about the 3D crack path.
News published in Agência FAPESP Newsletter about the scholarship: