Fixed Constraint, Interface
Use the Fixed Constraint, Interface to add a condition where the displacements constrained in all directions at interfaces between material layers in the selected geometric entity.
To constrain the actual material layers, use Fixed Constraint.
Interface Selection
Select the interface or interfaces for which this constraint is to be added.
When added: Exterior interfaces.
When Selected Interfaces is selected.
When added: Top interface.
When Selected Interfaces is selected.
Location in User Interface
Context Menus
Ribbon
Physics tab with Layered Shell selected: