Phase-field modeling of hydraulic fracturing in RVEs of heterogeneous materials

Resumo

Modeling hydraulic fracturing is a complex task, involving the occurrence of various physical phenomena, with the emergence of complex crack patterns, increased by the interaction between the fluid, the medium and the crack. It is, however, an indispensable subject for achieving efficiency and safety in various processes in the geotechnical sectors, the oil and gas extraction industry and structural engineering. Furthermore, most hydraulic fracturing applications deal with materials that are heterogeneous at a certain scale. At the microscopic level these materials, especially composite and natural materials, can be interpreted as a heterogeneous media formed by a series of components with different mechanical properties. Given that material damage begins with the appearance of microcracks at the microscale, and that these degraded regions can have their behavior affected by the presence of pressure load, the study of hydraulic fracture propagation in heterogeneous materials is a topic to be explored. In this sense, the aim of this work is to model the behavior of multiphase materials in pressure-driven fracture propagation scenarios. The phase-field model will be used, as it is an advantageous approach, capable of representing complex trajectories of numerous cracks directly without restricting their propagation directions and not demanding the use of additional techniques. Furthermore, this model allows the discretization of the different constituents of the material without the appearance of deformation concentration problems. Numerical results will be presented showing the influence of the pressure load on different random distributions of components in representative volume elements (RVEs) of quasi-brittle materials. The entire implementation was carried out using INSANE software, developed and made available by the Department of Structural Engineering at the Federal University of Minas Gerais (UFMG).