A hybrid FEMM-Phase field method for fluid-driven fracture propagation in three dimension.

In this paper, a new numerical simulation method named finite element meshfree-Phase field model (FEMM-PF) is presented and applied to simulate hydraulic fracture propagation in brittle medium. The deformation of matrix is calculated based on finite element-meshfree method (FEMM) which is a discrete approach to simulate fracture propagation without remeshing. The propagation of fractures is simulated by a smeared method named phase field (PF). FEMM-PF simulator inherits the capabilities of these two methods which can predict fracture propagation based on an energy criterion and also describe fractures in an explicit way. Because of the different fracture representation, a three dimension (3D) continuous-discontinuous strategy is introduced. The present method is designed to identify 3D sharp fracture surface within an evolving phase field band. First, discrete crack surface functional is used as switching criterion to govern this continuous-discontinuous transition process. Next, 3D crack-path identification algorithm is proposed to insert traction-free fracture segments. Finally, a staggered solution scheme is implemented to successive update displacement field and phase field. Several simulation examples in 3D quasi-static fracture mechanics are presented to verify the accuracy of FEMM-PF simulator, including modeling of fluid-driven fracture propagation, extension of notches and penny-shaped pressurized fractures propagation. [ABSTRACT FROM AUTHOR]