Computational modeling of crack propagation in fractured rocks using finite elements with high aspect ratio
Heber Agnelo Antonel Fabbri1; Osvaldo Luís Manzoli1; Pedro Rogério Cleto1; Eduardo Alexandre Rodrigues1; José Henrique Krähenbühl Ambiel1
1 Universidade Estadual Paulista
doi:10.20906/CPS/CILAMCE2017-0935
Resumo
This work presents a numerical method to modeling porous media containing pre-existing fracture networks. In this approach, the nonlinear behavior of the material is modeled in the context of the Finite Element Method (FEM), using the called Mesh Fragmentation Technique (MFT), which is based on the use of solid interface finite elements with high aspect ratio [1,2].These interface elements present the same kinematics as the continuous strong discontinuity approach (CSDA), being suitable to represent the formation of discontinuities associated with cracks, in a manner similar to cohesive models [3]. The pre-existing fractures are explicitly represented in the continuous material employing these interface elements, which are strategically positioned according to the geometry of the fracture network in the FE mesh. Thus, appropriate constitutive damage models are adopted to describe the complex failure behavior of material due to the behavior of pre-existing fractures, such as the fracture's surfaces contact, separation and slip, occurring concurrently with the crack initiation and propagation through the continuous porous media. Aiming to better understand the influence of the natural fractures on the failure process, the proposed model is applied to study the effect of individual and random multiple pre-existing fractures on the mechanical behavior of blocks under uniaxial tensile and compression load. [1] O.L. Manzoli, A. Gamino, E.A. Rodrigues and G. Claro, Modeling of interfaces in two-dimensional problems using solid finite elements with high aspect ratio. Computers and Structures, v. 94-95, p. 70-82, 2012. [2] O.L. Manzoli, M.A. Maedo, L.A.G. Bitencourt Jr., E.A. Rodrigues, On the use of finite elements with a high aspect ratio for modeling cracks in quasi-brittle materials. Engineering Fracture Mechanics, v. 153, p. 151-170, 2016. [3] J. Oliver and A.E. Huespe, Continuum approach to material failure in strong discontinuity settings, Computer Methods in Applied Mechanics and Engineering, 193, (30-32)
Palavras-chave: Interface finite element; Constitutive contactmodel; Natural Fractures; rocks