Comparisons of the size of the representative volume element in elastic, plastic, thermoelastic, and permeable random microstructures

The representative volume element (so-called RVE) is the cornerstone of continuum mechanics. In this paper we examine the scaling to RVE in linear elasticity, finite elasticity, elastoplasticity, thermoelasticity, and permeability of random composite materials. In order to compare the scaling to RVE between all these physical systems we introduce a discrepancy defined in terms of responses under uniform essential boundary conditions and uniform natural boundary conditions. Overall, the discrepancy is found to increase in the following order: linear elasticity, plasticity, linear thermoelasticity, nonlinear elasticity, and then permeability. However, the latter case cannot really be compared directly to other cases since the mismatch between solid and fluid phases in porous media is infinite.