Isotropic and Orthotropic Materials

Split the FeatureManager design tree such that the FeatureManager design tree and the COSMOS AnalysisManager tree can be seen at the same time.

To split the COSMOS AnalysisManager tree, place the pointer at the top of the COSMOS AnalysisManager tree until it changes to . Drag the bar down below the last item in the FeatureManager design tree. Then release the mouse to display the FeatureManager design tree, above the Section PropertyManager.

In the COSMOS AnalysisManager tree, select the component for which you want to define the orthotropic material. If you want to assign the orthotropic material to more than one component, hold down the Ctrl key while you click the component icons.
In the FeatureManager design tree, click the desired reference geometry.
In the COSMOS AnalysisManager tree, right-click your selection again and select Apply/Edit Material.

A message appears asking whether you want to update the reference geometry from Global to the reference geometry you selected in step 3.

Click Yes.

The Material dialog box opens.

In the Material model box, do the following:

Set Type to Linear Elastic Orthotropic.
Make sure that the selected reference appears in the Reference geometry box.
Select the desired Units.

Under Select material source, click Custom define.
In the material properties table, enter the numerical values of the material properties under the Value column.
Click OK.

Isotropic and Orthotropic Materials

Isotropic Materials

A material is isotropic if its mechanical and thermal properties are the same in all directions. Isotropic materials can have a homogeneous or non-homogeneous microscopic structures. For example, steel demonstrates isotropic behavior, although its microscopic structure is non-homogeneous.

Orthotropic Materials

A material is orthotropic if its mechanical or thermal properties are unique and independent in three mutually perpendicular directions. Examples of orthotropic materials are wood, many crystals, and rolled metals.

For example, the mechanical properties of wood at a point are described in the longitudinal, radial, and tangential directions. The longitudinal axis (1) is parallel to the grain (fiber) direction; the radial axis (2) is normal to the growth rings; and the tangential axis (3) is tangent to the growth rings.

Defining Orthotropic Properties For Solids

The orthotropic material directions throughout a component are defined based on the reference geometry selected. If a part is manufactured such that this is not true, then you should model it as different parts in order to define orthotropic directions properly. For example, consider the part shown in the figure:

You need to model this part as two parts; the cylinder and the planar sheet. You can then use a plane as the reference geometry for defining the orthotropic material directions for the planar sheet and the axis of the cylinder as the reference geometry for the cylinder.

Defining Orthotropic Properties For Shells

For a planar shell, select a plane that is parallel to the shell as the reference geometry. The X and Y axes lie in the plane and the Z-axis is normal to the plane. For a cylindrical shell, select the axis of the cylinder as the reference geometry. The Y-axis is parallel to the axis of the cylinder and the X-axis is tangential.


The X, Y, and Z directions for an orthotropic material when a plane is used as a reference geometry.	The radial (X), tangential (Y), and axial directions (Z) for an orthotropic material when an axis is used as a reference geometry.


The X, Y, and Z directions of an orthotropic material for a planar shell.	The X and Y directions of an orthotropic material for a cylindrical shell.