Computational homogenization of uncoupled consolidation in micro-heterogeneous porous media

Övrigt konferensbidrag, 2011

A Variational Multiscale Modeling framework, combined with a generalized macro-homogeneity condition, is exploited for the analysis of uncoupled quasistatic poromechanics problem in a strongly heterogeneous particle/matrix composite. Within this framework the classical approach of 1st order homogenization for stationary diffusion problems is extended to transient problems in a consistent manner. Homogenization is then carried out on representative volume elements (RVE’s), which are in practice introduced in quadrature points of the macroscale elements in the spatial domain. The modeling and computational strategy are applied to the transient problem of consolidation of geological materials which are strongly heterogeneous on the microscale. A typical example is asphalt-concrete consisting of a porous bitumen matrix and aggregates which are nearly impermeable. We consider a nearly-periodic micro-structure of particles embedded in a matrix. Without loss of generality but with considerable savings in computational effort, we restrict the analysis to 2D. Results obtained by solving the full-fledged micro-macroscale FE2 problem for the initial/boundary value problem will be discussed. In particular, we are interested in assessing the influence of the RVE size, the particle arrangement and local boundary conditions (Dirichlet/Neumann), on the subscale transient character.