Adding shells to a beam framework model in Mechanica?

[nlinesk8s]

My first post; bear with me if this is obvious and I missed it.

I've created a 2d framework model to represent a machine base. The beams were created from a sketched set of datum curves from proE. [using Toogood's tutorial book, as I almost always am doing solid analysis of thick parts, and not shells or beams]

The real base has plates welded onto the face of the beams in the framwork, so I'd like to add plates. However, if I go to the Insert menu, shells are greyed out. In a perfect world, I'd be able to pick the datum curves bounding the shell surface and it would create the shell. So much for that.

What do I need to do to allow a shell to be created? Do I need to create a surface in proE first?

thanks in advance for any help.

 

[nlinesk8s]

I'll add some info. I sketched a think extrusion on top of the datum curves in proE, and then was able to create a shell in Mechanica. But the model fails as unconstrained at the shell, so I assume the edges are not connected to the beams.

When I try to create a rigid link, I can't pick a shell edge, only the geometry of the extrusion and the datum curve from the beam element. The run fails, with error that the link is not attached to any elements.

This shouldn't be this hard. What's the secret?

 

[nlinesk8s]

I figured this out finally.

I first put a number of points on the datum curves making up my framework, in areas I would be creating the shells. I then sketched the extrusions for the shells using multiple line segments to those points. In Mechanica I compressed the shells and created elements as you would do normally, and assigned materials.