Defining brittle failure

When one, two, or all three local direct cracking strain or displacement components at a material point reach the value defined as the failure strain or displacement, the material point fails and all the stress components are set to zero. If all of the material points in an element fail, the element is removed from the mesh. See Brittle Failure Criterion, for more information.

  1. Create a material model as described in Defining a brittle cracking model.”
  2. From the Suboptions menu in the Edit Material dialog box, select Brittle Failure.

    A Suboption Editor appears.

  3. Select an option from the list of Failure criteria:

    • Select Unidirectional to indicate that an element will be removed when any local direct cracking strain (or displacement) component reaches the failure value.

    • Select Bidirectional to indicate that an element will be removed when any two direct cracking strain (or displacement) components reach the failure value.

    • Select Tridirectional to indicate that an element will be removed when all three possible direct cracking strain (or displacement) components reach the failure value.

  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. Enter the following data in the Data table:

    Direct cracking failure strain or displacement

    The value you enter depends on the method you chose in the Edit Material dialog box for specifying postcracking behavior (as described in Defining a brittle cracking model”).

    If you selected Strain, enter the direct cracking failure strain, (en⁢nc⁢k)f.

    If you selected Displacement or GFI, enter the direct cracking failure displacement, (unc⁢k)f. (Units of L.)

    Temp

    Temperature.

    Field n

    Predefined field variables.

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