Defining a brittle cracking model

The brittle cracking model in Abaqus/Explicit is most accurate in applications where the brittle behavior dominates and it is adequate to assume that the material is linear elastic in compression. You can use this model for plain concrete and for other materials such as ceramics or brittle rocks, but it is primarily intended for the analysis of reinforced concrete structures. See Cracking model for concrete, for more information.

  1. From the menu bar in the Edit Material dialog box, select MechanicalBrittle Cracking.

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

  2. Click the arrow to the right of the Type field, and select a method for defining the postcracking behavior:

    • Select Strain to specify the postcracking behavior by entering the postfailure stress-strain relationship directly.

    • Select Displacement to define the postcracking behavior by entering the postfailure stress/displacement relationship directly.

    • Select GFI to define the postcracking behavior by entering the failure stress and the Mode I fracture energy.

  3. Toggle on Use temperature-dependent data to define data that depend on 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 on which the data depend.

  5. If you selected Strain or Displacement from the list of Type options, enter the following data in the Data table:

    Direct stress after cracking

    Remaining direct stress after cracking, σtI. (Units of FL-2.)

    Direct cracking strain

    Direct cracking strain, en⁢nc⁢k. (Enter this value if you selected Strain from the list of Type options.)

    Direct cracking displacement

    Direct cracking displacement, unc⁢k. (Units of L.) (Enter this value if you selected Displacement from the list of Type options.)

    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.

  6. If you selected GFI from the list of Type options, enter the following data in the Data table:

    Failure stress

    Failure stress, σt⁢uI. (Units of FL-2.)

    Mode I fracture energy

    Mode I fracture energy, GfI. (Units of FL-1.)

    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. Select Brittle Shear from the Suboptions menu to define the postcracking shear behavior of the material. See Defining brittle shear” for details.

  8. If desired, select Brittle Failure from the Suboptions menu to specify the brittle failure criterion. See Defining brittle failure” for details.

  9. Click OK 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).