Antisymmetry
The Antisymmetry node adds a boundary condition for an antisymmetry boundary. An antisymmetry condition is fixed in the plane and free in the out-of-plane direction.
When applied to an edge (in the Membrane interface) the antisymmetry plane is formed by the normal to the boundary and the edge tangent.
The Antisymmetry node is only available with some COMSOL products (see http://www.comsol.com/products/specifications/).
Shell Properties

Constraint Settings
To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box.
In the COMSOL Multiphysics Reference Manual:
Location in User Interface
Context Menus
Ribbon
Physics tab with Solid Mechanics selected:
Physics tab with Membrane or Layered Shell selected: