Learning Forum

[wallybanger]

 

Hey guys, I have a 3"x3"x14ga steel tube that I'm trying to get to buckle and it won't.  It looks like a christmas tree every time I try to get results with the eignvalue buckling module.  It's a standard 50ksi steel material.

I understand that symetrical things don't like to buckle so I have tried offsetting the load slightly to one side and applying a side pressure to one of the sides.  Nothing.  Super annoying.

The support is a fixed support applied to the square profile (edge) at the base (surface mesh with a 2mm thickness).  At the top I have a remote displacement, applied to the top square profile (edge), that is set to zero for X and Y and Free for Z (I want it to compress the post).  It has a 0 rotation applied to the Z and free rotation for X and Y.  I want to simulate a beam, or 2 attached to the top so the tube can't spin but it can roll slightly in the x and y as it deforms.  My understanding is that this will only apply to that top edge so the side surfaces should be free to bow.

As I understand it this should be a standard 0.7L condition for Euler's Formula so I'm failing to understand why it won't work.  It's doing something, just not what I would expect/what should happen.

any input would be appreciated.

[Ashish Khemka]

Hi,

Please see if the examples presented here help:

Structural Instability Examples and Homework | Ansys Courses

Regards,

Ashish Khemka

[wallybanger]

OK, thank you, I will look at all of the examples and see if there is any usefull information to be gleaned.