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.
In the COMSOL Multiphysics Reference Manual:
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Constraint Reaction Terms
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Weak Constraints
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Constraint Settings
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Rigid body motion in the Structural Mechanics Modeling chapter.
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Rigid Motion Suppression Boundary Condition in the Structural Mechanics Theory chapter.
You can activate and deactivate this boundary condition by assigning it to a constraint group. See Load Cases in the Structural Mechanics Modeling chapter.
Location in User Interface
Context Menus
Solid Mechanics>Domain Constraints>Rigid Body Suppression
Shell>Face Constraints>Rigid Body Suppression
Plate>Face Constraints>Rigid Body Suppression
Membrane>Face Constraints>Rigid Body Suppression
Beam>Line Constraints>Rigid Body Suppression
Multibody Dynamics>Domain Constraints>Rigid Body Suppression
Ribbon
Physics tab with Solid Mechanics or Multibody Dynamics selected:
Domains>Domain Constraints>Rigid Body Suppression
Physics tab with Shell or Membrane selected:
Boundaries>Face Constraints>Rigid Body Suppression
Physics tab with Plate selected:
Domains>Face Constraints>Rigid Body Suppression
Physics tab with Beam or Truss selected:
Edges>Line Constraints>Fixed Constraint