Israr -
I'm not sure I understand your problem. If it is hinged on one side, then when you apply a force (by the jacks) then you will get rigid body motion. Since buckling depends on extracting eigenvectors, your model will have a mode at zero hertz (rigid body motion). What force or constraint resists the rotation of the flap? If you are trying to fix your model by balancing forces, be careful. Numerical round-off almost certainly assures the forces won't be balanced. This is one problem.
Secondly, you have interference between some parts in your assembly. I'm sure this causes problems with meshing. Try merging your assembly into a part file. Mechanica does this anyway with touching constraints. The only caveat would be if you need different material properties for the different parts.
Why are there shell idealizations in the model? I would use beam elements. If you try doing this with solid elements, good luck.
I will try to build a beam model, but in regards to your 'frustration' to the lack of response; this is not PTC customer support. Maybe they could help out with some more training classes. We help each other out in our spare time.
