This content has been marked as final.
Show 5 replies

Re: Euler Buckling using NL Analysis
Andy Krispie Mar 1, 2010 12:10 PM (in response to Andy Krispie)As a side note, I also attempted a more fundemetnal version of the same problem using a simple 50x50 solidsteelsquare bar & rocker assemply. Results were similar with a failure load well in excess of the critical Euler buckling load.
Re: Euler Buckling using NL Analysis
Bill McEachern Mar 1, 2010 12:47 PM (in response to Andy Krispie)I have done verification on Euler buckling before and it was right on the money. I don't think you need to do it in an NL study. You need BC's that allow axial freedom & a allow rotations or you won't get the right numbers. Using the remote load (restraint) would be the simplest way to get it done in a linear buckling study. I would put one together for you but I just don't have the time today.


Re: Euler Buckling using NL Analysis
Bill McEachern Mar 1, 2010 1:43 PM (in response to Andy Krispie)here is verification and the problem set up. Good luck.
buckling verification.png 65.5 KB

sq bar.SLDPRT.zip 45.9 KB


Re: Euler Buckling using NL Analysis
Anthony Botting Mar 1, 2010 2:43 PM (in response to Andy Krispie)Hi Andy: Yes, I have to concur with Bill on this. I have witnessed the Euler Buckling problem gets it righton, in Simulation. I suspect the difference you see is because the Euler Buckling problem is being solved in Simulation as a plain Eigenvalue/Eigenvector problem, whereas a nonlinear approach will likely produce a pathdependent answer. I have learned the Euler Buckling solution is nonconservative, but certainly useful for design. Moreover, actual test data for buckling problems have characteristically wide scatter. It is just too sensitive to minute variations in load, load position/offsets, load rate, temperature, material variations, geometry variations from manufacturing, boundary conditions, etc., as can be seen when trying to columnbuckle an unopened beer or soda can. That last example I am particularly fond of the experiment in school and we all got different answers in a controlled compression test machine  but it was really fun. 
Re: Euler Buckling using NL Analysis
Andy Krispie Mar 1, 2010 4:20 PM (in response to Andy Krispie)Excellent  definetely a boundary condition issue on my part. Thanks for the clarification and sample setup  much appreciated!