Impact Planes

Impact planes, only available in MES/nonlinear analyses, are rigid boundary surfaces that can have any orientation in 3D space. Automatic contact is allowed between impact planes and parts, but parts cannot penetrate the planes. You define impact planes to ensure all elements are on the correct side of the plane, as appropriate. You select from two types of impact planes - Slide/no bounce or Fully general. You can also vary impact plane settings to modify impact behavior and improve analysis convergence.

Define Impact Planes

To add an impact plane to your model, make the appropriate selections and entries in the Select Impact Plane dialog box. Click SetupContactsImpact PlanesNew to open the dialog box. Alternatively, with no objects selected in the graphics window, right-click in the display area away from the model and select Impact Planes.

Note: To edit an existing impact plane, expand the Impact Planes node in the browser, right-click the appropriate plane, and select Edit.

Plane sets the plane location

XY uses the global XY plane to define the impact plane
YZ uses the global YZ plane to define the impact plane
XZ uses the global XZ plane to define the impact plane
Advanced uses your equation to define the impact plane
3 Points uses the coordinates of 3 points to define the impact plane

Use Offset activates the offset input

X = offsets the impact plane from the global plane by the specified value

Type selects the impact plane type. Use Slide/no bounce if you do not want the object to leave the impact plane after contact - the object will slide along the plane. Use Fully general if you want the object to bounce off of the impact plane. Use Slide/no bounce only if the object should not bounce off the plane after contact. This type of plane will result in a shorter computing time.

Impact Plane Settings

To modify impact plane settings, click SetupContactsImpact PlanesSettings.

Contact Stiffness sets the stiffness of the virtual spring that connects the part to the impact plane

Automatic specifies the contact stiffness as 1% of the Young's modulus value for the softest material in the model - this is the default value
User-defined allows you to enter your own stiffness value

Note: If you specify too small a value for the stiffness, large penetration of nodes into the impact plane is inevitable. Too large a stiffness value leads to ill-conditioning of the global stiffness matrix and results in poor convergence.

Contact tolerance for planes specifies the distance within which the impact plane and object are said to be in contact. If the node and impact plane spacing are within this tolerance, the contact stiffness applies. Use a reasonably large value to prevent penetration of the impact plane.

Lowest time-step size controls how many times the processor reduces the time-step size to prevent the model from penetrating the impact plane

Tip: You can reduce the values for the tolerance and time-step size if your model is not converging as expected.