Eigenmode Imperfections - Postbuckling 2

[rybose]

Is there any way in Nastran to apply geometric imperfections for a postbuckling analysis?

In Abaqus, you can use the *Imperfection command to point to a results file of a buckling eigenvalue analysis.

*Imperfection, file=buckle_results
1, 0.05
2, 0.05
.. (specify mode number and max displacement)

I'm looking to a do the same thing in Nastran. Any suggestions?

Thanks

 

[ThomasH]

I think that what you are looking for is a nonlinear buckling solution. The exact approach depends a little on what "flavour" of Nastran you use and the licenses you have available.

There should be examples in the manual.

Regards

Thomas

 

[ESPcomposites]

How about just using a "small" lateral load? This should be enough to cause buckling to occur, which is similar to what ABAQUS is doing (though in a more convenient manner).

Brian

http://www.espcomposites.com

 

[jacksonfem]

At Femap-NxNastran, there is a command "move nodes to deform" and the nodes are "followin" the shape of a mode you want. But then you have to adjust the displacement.

Another way is to use the command "Create loads from loadset", creating loads at the vector of the deform mode you want, but you have to adjust the displacement caused by the loads using "Scale load" command.

I don 't know if i help you...