Decreasing mesh size gives strange results in buckling analysis 1

[Hich]

Dear all,

I am performing a buckling analysis on a I beam section under uniform moment. I use S4R element. as i decrease the mesh size sometimes I get very strange results that I don't know if they are real buckling modes or not. Does anybody have any idea about that?

Regards

 

[corus]

A coarse mesh will generally give a stiffer model which would affect the calculation of the buckling load. With a finer mesh you may pick up localised bucling effects, such as in the web and flanges. It'd be better if you posted a picture to get a better idea of what you're talking about.

Tara

http://tinyurl.com/4ydjg7m

 

[Hich]

Thank you Tara. Your answer helped a lot and it seams that when I make the mesh size too coarse local buckling contributes to the results.

Regards