Swelling Driven Cracking in Large Deformation in Porous Media

Ionized porous media, such as hydrogels, soft tissues, are considered as a saturated two-phase mixture, consist of a charged deformable solid skeleton and an interstitial fluid of opposite charge. Hydrogels subjected to changes of salt concentrations often develop cracks during swelling or shrinking. In return, the presence of discontinuities influences the swelling mechanics of the porous media, like swelling capacity. Therefore, it is strongly desirable to study the coupling between the fluid pressure and crack propagation. In biomedical engineering, hydrogel is a common physical model for soft tissues and consists of cross-linked ionized polymers. In this paper, we present a swelling driven fracture model for porous media in large deformation. Flow of fluid within the crack, within the medium and between the crack and the medium are accounted for. The partition of unity method is used to describe the displacement field and chemical potential field respectively. In order to capture the chemical potential gradient between the gel and the crack, an enhanced local pressure model is applied. A crack opening example is used to test the accuracy of the current model without the influence of the complexity of the crack propagation.