Supplementary material from "Nonlinear mode interaction in equal-leg angle struts susceptible to cellular buckling"

A formulation combining the Rayleigh–Ritz method and continuous displacement functions is used to derive a system of differential and integral equilibrium equations for the structural component. Solving the equations using numerical continuation reveals progressive cellular buckling (or snaking ) arising from the nonlinear interaction between the weak-axis flexural buckling mode and the strong-axis flexural–torsional buckling mode for the first time—the resulting behaviour being highly unstable.

Physical experiments conducted on 10 cold-formed steel specimens are presented and the results show good agreement with the variational model.