Linear Buckling Analysis

[sergio_duran]

Hi,

Quick question, why does the Linear Buckling Analysis only use Euler formula for all type of columns? Why doesn't it use Euler for long columns and Johnson for short columns?

BTW, the Column Calculator from Design Accelerator use more formulas (Rankine, Euler and Johnson) 

Thanks!

[John_Holtz]

Hi @sergio_duran 

To clarify, the buckling analysis is not "using the Euler formula". The Euler formula is based on the length and cross-sectional properties, and the analysis is not calculating any of that. The theory from which the Euler formula was derived is the basis of the buckling analysis; namely, buckling occurs when a loaded structure reaches a natural frequency of 0. That is, a compression load reduces the natural frequency, so there is some magnitude of load that causes the natural frequency to reduce from f1 to 0.

So the question is whether the other formulations (like Johnson or Rankine) have a way to be implemented for a general FEA. I do not know that answer, but I suspect the answer is no since there is no calculation of the "critical slenderness ratio" (at least for the Johnson formula).

I doubt that the even the Euler formula applies to anything more than 1 beam, and the analysis handles "plates" and "blobs" that can also buckle, not just uniform slender beams.

John