I've been doing some buckling analysis using simulation NL analysis, and after a bit of initial rigging have been quite pleased with the results.
I wanted to verify that my boundary conditions were behaving as expected, so I decided to conduct a basic buckling analysis of a W-Section (ie I-Beam) and compare it to the critical Euler buckling load. I used a W150x30 section (Iy=5.56e6 mm^4, ry=38.2mm). Assuming a slenderness ratio of kL/r=200, L=7640mm. Plugging that into the Euler critical buckling equation, Pc~188kN. I'm using 350W steel (E=200000MPa, Fy=350MPa) as a material.
I applied a constant lateral load of 2kN to create some initial displacement that would instigate buckling (worked out to ~3mm in this case). Attached are some images of my setup.
While I'm pleased with the buckling shape (visually K~1.0), the failure load of 547kN (+/- 5kN) is well above the critical buckling load. I've tried creating a very stiff material to use as the rocker component and increasing the lateral load but the failure results were within 5%. I would think simulating Euler buckling should be fairly simple, and I'm making a silly mistake. I thought someone out there might have some suggestions from past experience.