  Micro- and mesostructures of multiphase materials obtained from tomography
and image acquisition are an ever more important database for simulation
analyses. Huge data sets for reconstructed 3d volumes typically as voxel grids
call for criteria and measures to find an affordable balance of accuracy and
efficiency. The present work shows for a 3d mesostructure of concrete in the
elastic deformation range, how the computational complexity in analyses of
numerical homogenization can be reduced at controlled errors. Reduction is
systematically applied to specimen size S, resolution R, and discretization D,
which span the newly introduced SRD parameter space. Key indicators for
accuracy are (i) the phase fractions, (ii) the homogenized elasticity tensor,
(iii) its invariance with respect to the applied boundary conditions and (iv)
the total error as well as spatial error distributions, which are computed and
estimated. Pre-analyses in the 2d SRD parameter sub-space explore the
transferability to the 3d case. Beyond the concrete specimen undergoing elastic
deformations in the present work, the proposed concept enables
accuracy-efficiency balances for various classes of heterogeneous materials in
different deformation regimes and thus contributes to build comprehensive
digital twins of materials with validated attributes.
