Constraining the Solid Part

When constraining a part for thermal-structural analysis, it is important to avoid constraints that are too restrictive and lead to unrealistic stress concentrations. In this simulation, you constrain three mutually orthogonal surfaces on the manifold, thus preventing displacement in the direction normal to surfaces. This set of constraints prevents rigid body motion while allowing free expansion of the solid structure.

The manifold geometry contains appropriate surface patches on the XY and YZ planes, which, together with the cylinder head surface that lies on the XZ plane, provide a set of three mutually orthogonal surfaces.

As you apply the same type of constraint (normal displacement) on all surfaces, you require a single segment. To create the segment:

  1. Right-click the Regions > Manifold node and select Create Segment > Surface Segment.
  2. Rename the Manifold > Segments > Surface Segment 1 node to Zero Normal Displacement.
  3. Edit the Zero Normal Displacement node and set the following properties:
    Node Property Setting
    Zero Normal Displacement Surfaces
    • ExternalXMinus
    • ExternalZPlus
    • ToCylinderHead
    Type Constraint
    Physics Conditions > Solid Stress Constraints Method Normal Displacement
    Physics Values > Normal Displacement Value 0.0 m (default)
To visualize the constrained surfaces:
  1. Open the Manifold Geometry scene. In the simulation tree, select the Zero Normal Displacement segment node.


  2. Save the simulation.