CPA Help Pages
						Help for ANISOTROPIC
				An anisotropic (sometimes called aleotropic) material has different properties in different directions. The number of unique properties required to describe the materials response characteristics is dependent upon structural symmetry of the material. Orthotropic symmetry is commonly encountered in continuous fiber composites. This symmetry class is characterized by three mutually perpendicular planes of symmetry as illustrated below for a continuous fiber composite.
				For materials exhibiting orthotropic symmetry, 12 independent material descriptors are required to specify the behavior of the material. These are listed below:
				Hexagonal symmetry can be achieved through carefully controlled conditions which cause regular packing of the fibers. This symmetry class is illustrated in the Figure below.
				Because of this increased symmetry some of the material descriptors are equal so that only 7 independent material descriptors are required.
				Transverse isotropy is obtained when the packing geometry is of a random (disordered) form illustrated in the figure below.
				Here again 7 independent material descriptors are required and are exactly those given from Hexagonal Symmetry. For transversely isotropic and hexagonal symmetry, the indexing and relationships will be different if the "3" axis rather than the "1" axis is taken as the unique axis. Isotropic materials do not exhibit directional dependence. An example of an isotropic material can be obtained by replacing the fibers in the previous figure with spherical particles. This highest level of symmetry reduces the required number of material descriptors to 3.