A time-nonlocal multiphysics finite element method with Crank-Nicolson scheme for poroelasticity model with secondary consolidation
This work addresses computational challenges in geomechanics and civil engineering by improving efficiency and accuracy for modeling soil consolidation, though it appears incremental as it builds on existing finite element and time-stepping methods.
The paper tackled the poroelasticity model with secondary consolidation by developing a time-nonlocal multiphysics finite element method with a Crank-Nicolson scheme, achieving optimal-order error estimates and second-order temporal accuracy in numerical verification.
The paper studies a time-nonlocal multiphysics finite element method with Crank-Nicolson scheme for poroelasticity model with secondary consolidation. For the case where the physical parameters $λ,λ^*$ and $c_0$ are all finite positive constants, by introducing two auxiliary variables-the fluid content $η$ and the generalized pressure $ξ$ -- the original strongly coupled poroelasticity model is reformulated into a generalized Stokes equation with time integral terms and a diffusion equation. The reformulated model not only reveals the underlying multiphysics processes in the original model, but also exhibits time-nonlocal characteristics. A time-nonlocal multiphysics finite element method is designed for the reformulated model: the spatial discretization employs high order Taylor-Hood mixed finite element method, and the temporal discretization adopts the Crank-Nicolson scheme. The time integral terms are approximated using the composite trapezoidal rule, and the integral terms $J_ξ^n$ and $J_η^n$ are introduced for real-time updates, which not only avoids repeated calculations and improves efficiency, but also maintains second-order temporal accuracy. The existence and uniqueness of weak solutions for the reformulated model are proved via energy estimate methods, the stability of the fully discrete time-nonlocal multiphysics finite element method is established, and optimal-order error estimates are derived using projection operator techniques. Finally, numerical example verified the theoretical results and compared the long-time convergence of the Crank-Nicolson scheme and the backward Euler scheme.