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Fixed stress splitting approach for contact problems in a porous medium

Tameem Almani, Kundan Kumar

TL;DR

This work addresses a quasi-static poroelastic contact problem in a porous medium governed by the Biot equations with frictionless Signorini boundary conditions. It introduces a fully discrete fixed-stress splitting scheme that decouples flow and mechanics and uses backward Euler time stepping with Raviart-Thomas finite elements for the flow and a conforming discretization for the mechanics. A contraction analysis proves the scheme is contractive, yielding a bound that depends on beta = 1/(M alpha^2) + (c_f varphi_0)/alpha^2 + 1/lambda and a regularization term alpha^2/lambda; the contraction constant is (1/(lambda beta))^2. The results provide a stable, convergent method for simulating flow–geomechanics interactions in fractured porous media, with planned extensions to frictional contact and numerical validation.

Abstract

We consider a poromechanics model including frictionless contact mechanics. The resulting model consists of the Biot equations with contact boundary conditions leading to a variational inequality modelling mechanical deformations coupled to a linear parabolic flow equation. We propose a fully discrete iterative scheme for solving this model. This scheme decoupled the flow and mechanics equations and extends the fixed-stress splitting scheme for the Biot equations. We use finite elements in space and a backward Euler discretization in time. We show that the fixed stress split scheme is a contraction.

Fixed stress splitting approach for contact problems in a porous medium

TL;DR

This work addresses a quasi-static poroelastic contact problem in a porous medium governed by the Biot equations with frictionless Signorini boundary conditions. It introduces a fully discrete fixed-stress splitting scheme that decouples flow and mechanics and uses backward Euler time stepping with Raviart-Thomas finite elements for the flow and a conforming discretization for the mechanics. A contraction analysis proves the scheme is contractive, yielding a bound that depends on beta = 1/(M alpha^2) + (c_f varphi_0)/alpha^2 + 1/lambda and a regularization term alpha^2/lambda; the contraction constant is (1/(lambda beta))^2. The results provide a stable, convergent method for simulating flow–geomechanics interactions in fractured porous media, with planned extensions to frictional contact and numerical validation.

Abstract

We consider a poromechanics model including frictionless contact mechanics. The resulting model consists of the Biot equations with contact boundary conditions leading to a variational inequality modelling mechanical deformations coupled to a linear parabolic flow equation. We propose a fully discrete iterative scheme for solving this model. This scheme decoupled the flow and mechanics equations and extends the fixed-stress splitting scheme for the Biot equations. We use finite elements in space and a backward Euler discretization in time. We show that the fixed stress split scheme is a contraction.
Paper Structure (6 sections, 1 theorem, 18 equations)

This paper contains 6 sections, 1 theorem, 18 equations.

Key Result

theorem 1

Let $\beta = \frac{1}{M \alpha^2 } + \frac{c_f}{\alpha^2} \varphi_0 + \frac{1}{\lambda}$, the iterative scheme defined by eq:nf_eq4_fs_sr - eq:fixedstress2 is a contraction given by

Theorems & Definitions (4)

  • theorem 1
  • remark 1
  • remark 2
  • remark 3