Coupling Explicit Phase-field MPM for Two-Dimensional Hydromechanical Fracture in Poro-elastoplastic Media

Abstract

In this paper, a novel coupling explicit phase-field material point method with the convected particle domain interpolation (ePF-CCPDI) is proposed to predict the large deformation elastoplastic failure behavior in two-dimensional fully saturated porous media. This method provides a new thermodynamic derivation for the explicit phase-field modeling of multi-physical fracture problems. To account for the coupling effect of pore fluid flow on fractured porous solids, the pressure energy is included in the coupled system energy balance equation. The constitutive relationship of saturated porous media indicates that the pore pressure has a direct effect on the deformation of the solid skeleton. For achieving the fluid pressure smoothly distributed in damaged porous media under large deformation, exponential indicator functions are constructed to interpolate the fluid properties from the intact medium to the fully broken one. Meanwhile, the crack-opening-dependent permeability is introduced to estimate fluid flow inside the crack. The coupled explicit phase-field plasticity model is adopted to characterize the elastoplastic failure behavior of the solid skeleton. Moreover, a mixed explicit-implicit staggered solution scheme is developed to effectively solve the governing equations of the coupled system. To eliminate the numerical noises while material points cross the cell boundaries in large deformation simulation, the improved convected particle domain interpolation technique (CPDI) is adopted to enhance the computational accuracy. Two solution schemes are also proposed based on the extended material point penalty method to handle the specified pressure boundary condition. Finally, several representative two-dimensional numerical examples are conducted to validate the accuracy and capability of the proposed method.