In 3D, a solid can be connected to a shell by adding a Shell Connection node in the Solid Mechanics interface and a Solid Connection node in the Shell interface. The connection can either be from an edge of the shell to a boundary on the solid, or between two boundaries. The first case is intended for modeling a transition from a shell to a solid where shell assumptions are valid on both sides of the connection. The second case is for adding a shell on top of a solid.

The Shell Connection node is only available with some COMSOL products (see http://www.comsol.com/products/specifications/).

Select a Connected entity — Shell edge or Shell boundary.

When Shell edge is selected, select the name of the corresponding Solid Connection node defined at the edge level in the Shell interface to specify the connected parts.

Select an option from the Connected area defined by list: Shell thickness, Selected boundaries, or Distance from shell midsurface. This parameter determines how much of the selected solid boundaries are connected to the shell. The default is that a distance from the shell edge (having the size of the half the shell thickness in both directions) is connected. Using Selected boundaries connects the entire selected boundaries to the shell. If you select Distance from shell midsurface, enter a Distance d. This is used instead of the shell thickness for defining the connection distance.

For Shell boundary select the name of the corresponding Solid Connection node defined at the boundary level in the Shell interface to specify the connected parts.

Select a Boundary type — Shared or Parallel. For Parallel, select a Distance evaluation — Shell properties, Geometrical distance, or User defined. This parameter determines how the coupling treats the determination of the connection distance. The default is that a distance equal to half the shell thickness is used. If you select Geometrical distance, the connection distance is computed from the geometrical distance between the solid boundary and the shell boundary. For User defined enter a Distance d. This defines the connection distance.