Material Designer assumes that the material under consideration has a representative microscale structure: the representative volume element (RVE). This is a small volume of the material that is still large enough to exhibit the correct macroscopic material properties. For periodic materials, this can be easily identified as one unit cell. In a periodic material, this unit cell repeats itself in all three coordinate directions. Thus, it contains all the information about the material and it is sufficient to consider only the behavior of the single unit cell.

For non-periodic materials, identifying the size of an RVE is more complicated. One approach to investigate whether a considered volume is large enough to be representative is to increase the size of the volume and investigate whether the macroscopic properties change significantly. If this is the case, the initial volume was not large enough. If macroscopic properties remain fixed, the initial volume is likely suitable as an RVE. For a more detailed discussion of the concept of RVE and unit cell see [Kouznetsova] or [Li, et. al (2015)].

The homogenization process starts with modeling the RVE. This requires the creation of a simplified geometry, as well as the definition of material properties of the constituent materials. Subsequently, the geometry is meshed for finite element analysis. The RVE is then exposed to several macroscopic load cases, and its response is computed. The homogenized material data is computed from the results of these responses.