Specifying cohesive damage properties for mechanical contact property options

You can define damage initiation, evolution, and stabilization properties that will be accounted for in surface contact interactions. For more information, see Contact Cohesive Behavior.

  1. From the main menu bar, select InteractionPropertyCreate.
  2. In the Create Interaction Property dialog box that appears, do the following:

  3. Click Continue to close the Create Interaction Property dialog box.
  4. From the menu bar in the contact property editor, select MechanicalDamage.
  5. From the Initiation tabbed page, perform the following steps:
    1. From the Criterion list, choose one of the following:

      • Select Maximum nominal stress to specify a damage initiation criterion based on the maximum nominal stress criterion for cohesive elements.

      • Select Maximum separation to specify a damage initiation criterion based on the maximum separation value.

      • Select Quadratic traction to specify a damage initiation criterion based on the quadratic traction–interaction criterion for cohesive elements.

      • Select Quadratic separation to specify a damage initiation criterion based on the quadratic separation–interaction criterion for cohesive elements.

    2. Toggle on Use temperature-dependent data if the damage initiation behavior is dependent on temperature.
    3. Click the arrows to the right of the Number of field variables field to specify the number of field variables on which the damage initiation behavior depends.
    4. Enter the required data in the data table provided.
  6. If you want to specify damage evolution criteria; toggle on Specify damage evolution, click the Evolution tab, and perform the following steps:
    1. From the Type options, select one of the following:

      • Select Displacement to define the evolution of damage as a function of the total displacement (for elastic materials in cohesive elements) or the plastic displacement (for bulk elastic-plastic materials) after the initiation of damage.

      • Select Energy to define the evolution of damage in terms of the energy required for failure (fracture energy) after the initiation of damage.

    2. From the Softening options, select one of the following:

      • Select Linear to specify a linear softening stress-strain response (after the initiation of damage) for linear elastic materials or a linear evolution of the damage variable with deformation (after the initiation of damage) for elastic-plastic materials.

      • Select Exponential to specify an exponential softening stress-strain response (after the initiation of damage) for linear elastic materials or an exponential evolution of the damage variable with deformation (after the initiation of damage) for elastic-plastic materials.

      • Select Tabular to specify the evolution of the damage variable with deformation (after the initiation of damage) in tabular form. This option is available only for damage evolution defined in terms of displacement.

    3. If you want to specify mode-dependent behavior, toggle on Specify mixed mode behavior and select one of the following options:

      • Select Tabular to specify the fracture energy or displacement (total or plastic) directly as a function of the shear-normal mode mix for cohesive elements. This method must be used to specify the mixed-mode behavior for cohesive elements when damage evolution is defined in terms of displacement.

      • Select Power law to specify the fracture energy as a function of the mode mix by means of a power law mixed-mode fracture criterion.

      • Select Benzeggagh-Kenane to specify the fracture energy as a function of the mode mix by means of the Benzeggagh-Kenane mixed-mode fracture criterion.

    4. If you specified Tabular for the mixed mode behavior, select one of the following:

      • Select Energy to define the mode mix in terms of a ratio of fracture energy in the different modes.

      • Select Traction to define the mode mix in terms of a ratio of traction components.

    5. If you toggled on Specify mixed mode behavior and selected either Power law or Benzeggagh-Kenane as the fracture criterion, you can specify the exponent in the power law or the Benzeggagh-Kenane criterion that defines the variation of fracture energy with mode mix for cohesive elements. Toggle on Specify power-law/criterion and enter a value for the exponent in the field.
    6. Toggle on Use temperature-dependent data if the damage evolution behavior is dependent on temperature.
    7. Click the arrows to the right of the Number of field variables field to specify the number of field variables on which the damage evolution behavior depends.
    8. Enter the required data in the data table provided.
  7. If you want to specify viscous regularization of the constitutive equations defining surface-based cohesive behavior; toggle on Specify damage stabilization, click the Stabilization tab, and specify a viscosity coefficient.
  8. Click OK to create the contact property and to exit the Edit Contact Property dialog box. Alternatively, you can select another contact property option to define from the menus in the Edit Contact Property dialog box.