Two-way coupled multiphysics simulation of lattice discrete particle model

In this study, a Multiphysics-Lattice Discrete Particle Model (M-LDPM) framework that deals with coupled-fracture-poroflow problems has been introduced. The M-LDPM framework uses two lattice systems, the LDPM tessellation and the Flow Lattice Element (FLE) network, to represent the heterogeneous internal structure of typical quasi-brittle materials like concrete and rocks, and to simulate the material’s mechanical behavior and mass transport at the coarse aggregate scale. In this study, the LDPM governing equations are revisited and modified to include the influence of fluid pore pressure. The governing equations of the Flow Lattice Model (FLM) for pore pressure flow are derived using mass conservation balances for both uncracked and cracked specimens. The proposed M-LDPM framework was implemented using Abaqus user element subroutine VUEL for mechanical behavior within the explicit dynamic procedure and user subroutine UEL for mass transport within the implicit transient procedure. The coupling of the two models was achieved using Interprocess Communication (IPC) between Abaqus solvers. The M-LDPM framework can simulate the variation of permeability induced by fracturing processes by relating the transport properties of flow elements with local cracking behaviors. The proposed model is validated by comparing the numerical results with analytical solutions of classical benchmarks found in poromechanics literature.