Rigid Connector, Interface
The Rigid Connector is a boundary condition for modeling rigid regions and kinematic constraints such as prescribed rigid rotations. The selected shell faces will move as a single rigid object, irrespective of whether they are geometrically adjacent or not.
To add a rigid connector to the edge of the shell, use Rigid Connector.
If the study step is geometrically nonlinear, the rigid connector takes finite rotations into account. The feature is similar to the rigid connectors in the Solid Mechanics and Beam interfaces. Rigid connectors from the Shell, Beam and Solid Mechanics interfaces can be attached to each other.
You can add functionality to the rigid connector through the following subnodes.
Applied Force (Rigid Connector) to apply a force in given point.
Mass and Moment of Inertia (Rigid Connector) to add extra mass and moment of inertia in a given point.
Spring Foundation (Rigid Connector) to add a translational or rotational spring or damper in a given point.
Interface Selection
Select the interface or interfaces for which this spring condition is to be added.
When added: Exterior interfaces.
When Selected Interfaces is selected.
All other settings for the Rigid Connector, Interface node are described in the documentation for Rigid Connector in the Solid Mechanics interface.
Context Menus
Ribbon
Physics tab with  Layered Shell selected: