Defining brittle shear

An important feature of the cracking model is that, while crack initiation is based on Mode I fracture only, postcracked behavior includes Mode II as well as Mode I.

Context:

Mode II shear behavior is based on the common observation that the shear behavior depends on the amount of crack opening. More specifically, the cracked shear modulus is reduced as the crack opens. Therefore, Abaqus/Explicit offers a shear retention model in which the postcracked shear stiffness is defined as a function of the opening strain across the crack.

You must provide postcracking shear data to complete a brittle cracking model definition. See Shear Retention Model, 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 Shear.

    A Suboption Editor appears.

  3. Click the arrow to the right of the Type field, and select a method for specifying postcracking shear behavior:

    • Select Retention Factor to specify the postcracking shear behavior by entering the shear retention factor-crack opening strain relationship directly.

    • Select Power Law to specify the postcracking shear behavior by entering the mateiral parameters for the power law shear retention model.

  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 Retention Factor from the list of Type options, enter the following data in the Data table:

    Shear retention factor

    Shear retention factor, ρ.

    Crack opening strain

    Crack opening strain, en⁢nc⁢k.

    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 Power Law from the list of Type options, enter the following data in the Data table:

    e and p

    Material parameters em⁢a⁢xc⁢k and p.

    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.