# Creating a porous elastic material model

 A porous elastic material model defines the elastic parameters for a porous material. For more information, see Elastic behavior of porous materials.
1. From the menu bar in the Edit Material dialog box, select MechanicalElasticityPorous Elastic.

(For information on displaying the Edit Material dialog box, see Creating or editing a material.)

2. Click the arrow to the right of the Shear field and select an option for defining deviatoric elastic behavior in the porous material:

• Select G to specify a constant shear modulus. In this case the shear behavior is unaffected by compaction of the material.

A Shear Modulus column appears in the Data table.

• Select Poisson to allow Abaqus to calculate the instantaneous shear modulus from the bulk modulus and Poisson's ratio. In this case, the elastic shear stiffness increases as the material is compacted.

A Poisson's ratio column appear in the Data table.

3. To define behavior data that depend on temperature, toggle on Use temperature-dependent data.

A column labeled Temp appears in the Data table.

4. To define behavior data that depend on field variables, click the arrows to the right of the Number of field variables field to increase or decrease the number of field variables.

Field variable columns appear in the Data table.

5. In the Data table, enter the material parameters:

Log Bulk Modulus

Logarithmic bulk modulus, $κ$. (Dimensionless.)

G

Shear modulus, G. Enter this value if you selected G from the list of Shear options.

Poisson's ratio

Poisson's ratio, $ν$. Enter this value if you selected Poisson from the list of Shear options.

Tensile Limit

Elastic tensile limit, $pte⁢l$. (This value cannot be negative.)

Temp

Temperature, $θ$.

Field n

Predefined field variables.

You may need to expand the dialog box to see all the columns in the Data table. For detailed information on how to enter data, see Entering tabular data.

6. Click to create the material and to close the Edit Material dialog box. Alternatively, you can select another material behavior to define from the menus in the Edit Material dialog box (see Browsing and modifying material behaviors, for more information).