Hello Gentlemen, 

I am a new user of Solid works ( University Projects), and i have a problem using static simulation mesh control, 

The problem is, i have a rectangular duct with wall thickness 3 mm, (shell)

the duct is complete part not assembly, please check the attached picture

When i start the static simulation, i checked the mesh control, and it always fails to complete because of "Shell", when i delete the shell in the sketch, the mesh succeeded, but surely its nor correct 

Thank you