Shell–Beam Connection
Add the Shell–Beam Connection multiphysics node () to create transitions between boundaries or edges modeled using the Shell interface and edges or points modeled using the Beam interface.
The Shell–Beam Connection node is only available with some COMSOL products (see https://www.comsol.com/products/specifications/).
Connection Settings
Select the Connection type — Shell edges to beam points, Shared edges, Parallel edges, or Shell boundaries to beam points.
For all options except Parallel edges, there is an automatic search for possible adjacent geometrical objects. If you want to modify the selections, select the Manual control of selections check box. If you clear it again, the selections will be replaced by the automatic ones.
Shell Edges to Beam Points
If the automatic selection is not sufficient, select the Manual control of selections check box. Then, select the connected shell edges in the Edge Selection, Shell section and the corresponding beam points in the Point Selection, Beam section.
Select a Connected region — Selected edges, Distance (automatic), Distance (manual), or Connection criterion.
•
Using Selected edges makes all selected edges rigidly connected to the point on the beam.
•
For Distance (automatic), all parts on the shell edge, which are within the default distance from the beam point, are connected. This distance is determined by the cross section properties of the beam. It is contained in the variable beam.re as described in the documentation for The Beam Interface.
•
For Distance (manual) enter a Connection radius rc. All parts on the shell edge, which are within the given distance from the beam point, are connected.
•
For Connection criterion enter a Boolean expression in the text field. The beam is connected to the selected shell edge wherever the expression has a nonzero value. The default value is 1, which is equivalent to using the Selected edges option.
Shared Edges
If the automatic selection is not sufficient, select the Manual control of selections check box. Then, select the connected edges in the Edge Selection section.
Select an Offset definition — Along shell normal or Offset vector.
•
For Along shell normal enter an Offset ζ.
•
For Offset vector enter values for d0 in the table. The offset is the vector from the reference surface of the shell to the actual position of the beam.
Parallel Edges
Enter a value for the Parallelism tolerance Δθ. The default is 1 degree. The two edges are connected only where they are parallel within the specified tolerance.
Shell Boundaries to Beam Points
If the automatic selection is not sufficient, select the Manual control of selections check box. Then, select the connected shell boundaries in the Boundary Selection, Shell section and the corresponding beam points in the Point Selection, Beam section.
Select an option from the Connected region list — Selected boundaries, Distance (automatic), Distance (manual), or Connection criterion.
•
Using Selected boundaries makes all selected boundaries rigidly connected to the point on the beam.
•
For Distance (automatic), all parts on the shell boundary, which are within a default distance from the beam point, are connected. This distance is determined by the cross section properties of the beam. It is contained in the variable beam.re as described in the documentation for The Beam Interface.
•
For Distance (manual) enter a Connection radius rc. All parts on the shell edge, which are within the given distance from the beam point, are connected.
•
For Connection criterion enter a Boolean expression in the text field. The beam is connected to the selected shell boundary wherever the expression has a nonzero value. The default value is 1, which is equivalent to using the Selected boundaries option.
•
For more information about coupling different element types, see Coupling Techniques.
•
For details about the formulation of this coupling, see Connection Between Shells and Beams
These types of couplings will commonly generate many constraints, possibly even conflicting with other constraints coming from ordinary boundary conditions. For methods of resolving potential problems, see
•
Elemental and Nodal Constraints
•
Suppressing Constraints on Lower Dimensions
When there are many interconnected constraints, it may also be useful to change Null-Space Function to Orthonormal or Explicit — Orthonormal, but doing so may increase the memory consumption significantly.
Examples of all types of couplings between shells and beams are shown in Connecting Shells and Beams: Application Library path Structural_Mechanics_Module/Beams_and_Shells/shell_beam_connection