Shells with no stiffness

Certain modeling techniques involve using shells in a manner where they do not contribute to the stiffness of the structural system. An example of this is where area objects collect distributed loading and transfer forces to coincident joints on the structure.

This may be accomplished using either of the following two methods:

• Define shell objects with their actual thickness, then assign property modifiers to significantly reduce shell stiffness, perhaps by a factor of 10^-3 or 10^-4.

• Use null areas, which are area objects with a None area section assignment, to apply loads using the Uniform to Frame (Shell) load assignment.