Homogenization of discrete diffusion models by asymptotic expansion

TL;DR

This paper introduces an asymptotic expansion homogenization scheme for discrete diffusion models, enabling efficient multiscale analysis of heterogeneous materials by reducing computational costs while maintaining accuracy.

Contribution

It develops a homogenization method that separates macroscale and mesoscale descriptions, simplifying the RVE problem to a linear steady-state form for efficient computation.

Findings

Significant reduction in computational time for discrete diffusion problems.

Homogenization introduces negligible error mainly from macroscale finite element discretization.

Applicable to both transient and steady-state nonlinear diffusion models.

Abstract

Diffusion behaviors of heterogeneous materials are of paramount importance in many engineering problems. Numerical models that take into account the internal structure of such materials are robust but computationally very expensive. This burden can be partially decreased by using discrete models, however even then the practical application is limited to relatively small material volumes. This paper formulates a homogenization scheme for discrete diffusion models. Asymptotic expansion homogenization is applied to distinguish between (i) the continuous macroscale description approximated by the standard finite element method and (ii) the fully resolved discrete mesoscale description in a local representative volume element (RVE) of material. Both transient and steady-state variants with nonlinear constitutive relations are discussed. In all the cases, the resulting discrete RVE problem becomes a simple linear steady-state problem that can be easily pre-computed. The scale separation provides a significant reduction of computational time allowing the solution of practical problems with a negligible error introduced mainly by the finite element discretization at the macroscale.