Defining pressure-driven mass diffusion

The pressure stress factor, κp, governs mass diffusion driven by the gradient of the equivalent pressure stress. You can define the pressure stress factor as a function of concentration, temperature, and/or field variables. See Diffusivity, for more information.

  1. Define diffusivity as described in Defining diffusivity.”

  2. From the Suboptions menu in the Edit Material dialog box, select Pressure Effect.

    A Suboption Editor appears.

  3. Toggle on Use temperature-dependent data to define the pressure stress factor as a function of temperature.

    A column labeled Temp appears in the Data table.

  4. Click the arrows to the right of the Number of field variables field to increase or decrease the number of field variables included in the definition of the pressure stress factor.

  5. Enter the following data in the Data table:

    kappa_p

    Pressure stress factor, κp. (Units of LF−1/2.)

    Concentration

    Mass concentration of the diffusing material.

    Temp

    Temperature.

    Field n

    Predefined field variables.

  6. Click OK to return to the Edit Material dialog box.