Constituents of a Lamina
A lamina, in general, consists of fibers in a matrix. The homogenized properties of a lamina depend on the material properties of the fibers and the matrix, and on their distribution. The fibers are in general orthotropic, whereas the filler material is isotropic.
Figure 2-2: Example of a unit cell of a lamina having fiber and matrix materials.
A repeating unit cell (RUC) or representative volume element (RVE), is the smallest volume element which can be repeated to describe the full lamina. An example of a unit cell is shown in Figure 2-2, where it is assumed that the fibers are located on a regular square lattice. With this RUC, the volume fraction of fibers is sufficient to describe the fiber content in the lamina. The length of the RUC in the fiber direction is immaterial, while the size in the two transverse directions is given by the spacing between fibers.