Structural Test Rig 3D: Euler Column Buckling and Beam Bending under a Rising Load

In column mode the rig squeezes a slender aluminium column with a rising load P = R t; the lateral deflection is drawn 30 times exaggerated and the arrow turns from green to red as P approaches the Euler load Pcr = pi^2 EI/(K L)^2, after which the column is shown buckled. The deflected shape is sketched: half-sine for K = 1, (1 - cos 2 pi x/L)/2 for K = 0.5, a cubic for K = 0.7 and the cantilever curve for K = 2. In beam mode the beam is supported as chosen (simply supported, fixed-fixed or cantilever) and bends with the central or tip load, drawn 14 times exaggerated.

All numbers come from the same physics.mjs solver as the 2D companion (tridiagonal finite differences and closed-form checks below), so both pages agree. Drag to orbit, scroll or pinch to zoom.