Editors: | F. Kongoli, E. Aifantis, A. Chan, D. Gawin, N. Khalil, L. Laloui, M. Pastor, F. Pesavento, L. Sanavia |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2019 |
Pages: | 190 pages |
ISBN: | 978-1-989820-06-3 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
The present work models problems in which the initiation and propagation of cracks in porous materials represents a key issue and is strongly influenced by the interaction between the solid matrix and the fluid in pores. The methodology is based on a work by the authors already published [1].
In this case, discontinuities are modelled by means of quasi-zero-thickness interface elements using an FEM-based approach. These special elements, which can be used to define either pre-existing or propagating cracks, act as joints that allow representation of the jump in the displacement field and the directional preferences in the fluid flow.
To ensure that the direction of the crack growth is not heavily influenced by the mesh, a non-local damage model is used to predict the degradation pattern of the domain and the interface elements are then inserted, followed by a remeshing.
FIC-stabilized elements of equal order interpolation in the displacement and the pore pressure have been successfully used under complex conditions near the undrained-incompressible limit [2]. A bilinear cohesive fracture model describes the mechanical behaviour of the joints. A formulation derived from the cubic law models the fluid flow through the crack.
Examples in 2-D and 3-D, using 3-noded triangles and 4-noded tetrahedra respectively, are presented to illustrate the features of the proposed methodology in hydraulic fracture processes. Other examples solved by the authors using joint elements in dam engineering [3] will be shown to introduce some of their alternative applications.