  This paper presents a new adaptive multiscale homogenization scheme for the
simulation of damage and fracture in concrete structures. A two-scale
homogenization method, coupling meso-scale discrete particle models to macro-
scale finite element models, is formulated into an adaptive framework. A
continuum multiaxial failure criterion for concrete is calibrated on the basis
of fine-scale simulations, and it serves as the adaptive criterion in the
multiscale framework. Thus, in this approach, simulations start without
assigning any material Representative Volume Element (RVE) to the macro-scale
finite elements. The finite elements that meet the adaptive criterion and must
be entered into the multiscale homogenization framework are detected on the
fly. This leads to a substantial reduction of the computational cost especially
for loading conditions leading to damage localization in which only a small
portion of the FE mesh is enriched with the homogenized RVE. Several numerical
simulations are carried out to investigate the capability of the developed
adaptive homogenization method. In addition, a detailed study on the
computational cost is performed.
