Applying Tangential Behavior Overrides

You can use a tangential behavior override to override contact interaction property definitions. Use tangential behavior override to change the tangential behavior values of a contact interaction property for a subsequent step in your simulation.

Tangential behavior override features are available for general static, quasi-static, and implicit dynamic steps. For a given contact interaction property, you can create a single tangential behavior override.

Before you begin: Define a contact interaction property.
See Also
About Tangential Behavior Overrides
  1. From the Interactions section of the action bar, click Tangential Behavior Override .
  2. Optional: Enter a descriptive Name.
  3. Select the Contact interaction property instance that you want to override.
  4. Select one of the following as the Friction type:
    OptionDescription
    Coulomb Relates the maximum allowable frictional (shear) stress across an interface to the contact pressure between the contacting bodies.
    Rough Prevents all relative sliding motion between two contacting surfaces as long as the corresponding normal-direction contact constraints are active.
  5. Select one of the following as an Enforcement:
    OptionDescription
    Penalty Enforces frictional constraints with a stiffness, which permits some relative motion of the surfaces (an "elastic slip") when they should be sticking.
    Lagrange Enforces sticking constraints exactly so there is no relative motion between two closed surfaces until the critical shear stress is reached.
  6. Optional: Select one or more of the following Frictional Dependencies to create a dependency between the friction coefficient and another variable:
    • Slip rate: Velocity parallel to the surface when friction is overcome.
    • Contact pressure: Pressure between two surfaces in contact.
    • Temperature: Temperature of the contact surface.
    A table appears with columns for the friction coefficient and for the dependencies you select. You can directly enter the data in the table, or you can import the data from an external file by right-clicking in the table.
  7. Optional: Enter a Friction coefficient.

    The friction coefficient is the ratio between the critical shear stress (the point at which contacting surfaces start slipping) and the contact pressure.

  8. Optional: Enter a value for Tau max.

    Tau max is the equivalent shear stress limit; that is, the maximum achievable value of the equivalent shear stress. Sliding occurs if the magnitude of the equivalent shear stress reaches this value, regardless of the magnitude of the contact pressure stress.

  9. Optional: Enter a Slip tolerance.

    The slip tolerance is the magnitude of allowable elastic slip when using the penalty enforcement method.

  10. Click OK.