Defining sorption

From the menu bar in the Edit Material dialog box, select OtherPore FluidSorption.

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

Display the Absorption tabbed page.

Click the arrow to the right of the Law field, and specify how you want to define absorption behavior:

• Select Log to define absorption behavior by the analytical logarithmic form.

• Select Tabular to define absorption behavior in tabulated form.

If you selected Log in the previous step, enter the following data in the Data table:

A

A. This value must be positive. (Dimensionless.)

B

B. This value must be positive. (Units of L²F⁻¹.)

s0

$s_0$. This value must lie in the range $0.01\le s_0<s_1<0.9$. The default is 0.01.

s1

$s_1$. This value must lie in the range $0.01\le s_0<s_1<0.9$. The default is 0.01 plus a very small positive number (since $s_1$ cannot be equal to $s_0$).

If you selected Tabular in Step 3, enter the following data in the Data table:

Pore Pressure

Pore pressure, $u_w$, with the condition $u_w\le 0.0$. (Units of FL⁻².)

Saturation

Saturation, s. This value must lie in the range $0.01\le s\le 1.0$

If you want to include exsorption behavior in the sorption definition, display the Exsorption tabbed page, and toggle on Include exsorption. Otherwise, skip to Step 12.

Click the arrow to the right of the Law field, and specify how you want to define exsorption behavior:

• Select Log to define exsorption behavior by the analytical logarithmic form.

• Select Tabular to define exsorption behavior in tabulated form.

Toggle on Include scanning to define the behavior between absorption and exsorption by a scanning line of constant slope, ${\left(d{u}_w/ds\right)|}_s$. This slope should be larger than the slope of any segment of the absorption or exsorption behaviors.

If you define sorption behavior without specifying a scanning line slope, Abaqus uses a slope of 1.05 times the largest value of $d{u}_w/ds$ provided in the absorption and exsorption behavior definitions.

If you toggled on Include scanning, enter a value for the slope of the scanning line in the Slope field.

If you selected Log in Step 7, enter the following data in the Data table:

A

A. This value must be positive. (Dimensionless.)

B

B. This value must be positive. (Units of L²F⁻¹.)

s0

$s_0$. This value must lie in the range $0.01\le s_0<s_1<0.9$. The default is 0.01.

s1

$s_1$. This value must lie in the range $0.01\le s_0<s_1<0.9$. The default is 0.01 plus a very small positive number (since $s_1$ cannot be equal to $s_0$).

If you selected Tabular in Step 7, enter the following data in the Data table:

Pore Pressure

Pore pressure, $u_w$, with the condition $u_w\le 0.0$. (Units of FL⁻².)

Saturation

Saturation, s. This value must lie in the range $0.01\le s\le 1.0$

Click OK 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).