Rigid Motion Suppression
The Rigid Motion Suppression node adds a minimum number of constraints required to suppress any rigid body modes. The constraints are selected so that there will be no reaction forces if the external loads are self-equilibrating.
The constraint will, depending on physics interface and geometrical dimension, be applied to one, two, or three points as needed. These points are automatically picked from the selected geometrical objects.
If you need to constrain several objects which are not physically connected, you must add as many Rigid Motion Suppression nodes as there are disconnected objects.
Layer Selection
This section is only present in the in the Layered Shell interface, where it is described in the documentation for the Rigid Motion Suppression node.
In the COMSOL Multiphysics Reference Manual:
Location in User Interface
Context Menus
Solid Mechanics>Domain Constraints>Rigid Motion Suppression
Shell>Face Constraints>Rigid Motion Suppression
Plate>Face Constraints>Rigid Motion Suppression
Layered Shell>Face Constraints>Rigid Motion Suppression
Membrane>Face Constraints>Rigid Motion Suppression
Beam>Line Constraints>Rigid Motion Suppression
Multibody Dynamics>Domain Constraints>Rigid Motion Suppression
Ribbon
Physics tab with Solid Mechanics or Multibody Dynamics selected:
Domains>Domain Constraints>Rigid Motion Suppression
Physics tab with Shell or Membrane selected:
Boundaries>Face Constraints>Rigid Motion Suppression
Physics tab with Plate selected:
Domains>Face Constraints>Rigid Motion Suppression
Physics tab with Layered Shell selected:
Boundaries>Face and Domain Constraints>Rigid Motion Suppression
Physics tab with Beam or Truss selected:
Edges>Line Constraints>Fixed Constraint