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Effective Properties of Periodic Structures
Sometimes you need to model on different scales. The heterogeneous properties of a material in the microscopic scale are often unfeasible to use directly on a macroscopic scale, in which a structure is typically analyzed. In such a case, you typically want to use a homogeneous material model with appropriately averaged properties.
The
Cell Periodicity
feature facilitates the evaluation of such average properties. It is based on the idea of a
representative volume element
(RVE). The RVE is a domain that is representative for the material on a microscopic scale.
If the material is truly periodic, an RVE is typically identified as the smallest possible unit cell. If the material has a random distribution of, for example, porosities, the RVE should be large enough to be representative for the average properties of the material on a macroscopic scale.
The only requirement on the shape of the RVE is that it should be possible to fill space with a repetitive pattern of RVEs. This means that there are a set of matching boundary pairs, each pair having the same geometry, but offset by a given distance.