Defining Drucker-Prager creep

You can define classical “creep” behavior of materials that exhibit plasticity according to the extended Drucker-Prager models in Abaqus/Standard analyses. The creep behavior in such materials is intimately tied to the plasticity behavior (through the definitions of creep flow potentials and definitions of test data), so you must include both Drucker-Prager plasticity and Drucker-Prager hardening data in the material definition.

Context:

The creep data that you enter must be consistent with the Hardening behavior type that you select when defining Drucker-Prager hardening (see Defining Drucker-Prager hardening” for details).

For more information, see Creep models for the linear Drucker-Prager model.

  1. Create a material model as described in Defining a Drucker-Prager model.”

  2. From the Suboptions menu in the Edit Material dialog box, select Drucker Prager Creep.

    A Suboption Editor appears.

  3. Click the arrow to the right of the Law field, and select the creep law option of your choice:

    • Select Strain to choose a strain hardening power law.

    • Select Time to choose a time hardening power law

    • Select SinghM to choose a Singh-Mitchell type law.

    • Select User to specify the creep law with user subroutine CREEP.

    For more information, see Specifying a creep law.

  4. Toggle on Use temperature-dependent data to define data that depend on temperature.

    A column labeled Temp appears in the Data table.

  5. Click the arrows to the right of the Number of field variables field to increase or decrease the number of field variables on which the data depend.

  6. If you selected either the Strain or the Time creep law option, enter the following data in the Data table:

    A, n, and m

    Creep material parameters.

    Temp

    Temperature.

    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.

  7. If you selected the SinghM creep law option, enter the following data in the Data table:

    A, alpha, m, and t1

    Creep material parameters A, α, t1, and m.

    Temp

    Temperature.

    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.

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