ProE Mechanica, Buckling Perpendicular to the Load?!

[vonsteimel]

Greetings,
See the attachment.

I've been refreshing my memory of Pro/mechanica (Wildfire 2.0) and have ran into an odd problem.

I've built 2 quick beams. One is straight across, the other (shown in the attachment) has a small section removed. I've been running buckling analysis on them.

The first beam works fine. This one with a section removed, however, does not. Everything seems to come out alright but it is buckling perpendicular to the load!? Looked over everything multiple times but cannot figure out what is wrong.

Any suggestions?

Thanks,

VS

 

[vonsteimel]

I had originally tried setting it up with allowing translation in the "X" direction for one of the constraints -- and it worked well with the full beam but had a "fatal error" anytime I tried it on the one with the removed section.

 

[shaun8567]

Can you upload the model itself? Have you looked the the 2nd, 3rd, and 4th mode of buckling? Are you meshing the geometry with solid elements? If so, be aware that the rotational DOFs on your constraint are NOT locked; solid elements only have three DOF per node (all translation).

"I had originally tried setting it up with allowing translation in the "X" direction for one of the constraints -- and it worked well with the full beam but had a "fatal error" anytime I tried it on the one with the removed section."

Might be a singular stiffness matrix. Try running a modal analysis with rigid body modes checked to see if you have any rigid body motion.