Variational modelling of local–global mode interaction in long rectangular hollow section struts with Ramberg–Osgood type material nonlinearity

A variational model describing the nonlinear mode interaction in thin-walled box-section struts under pure axial compression made from a material obeying Ramberg–Osgood law is presented. The formulation combines continuous displacement functions and generalized coordinates, leading to derivation of system differential integral equations that describe static equilibrium response strut. Solving using numerical continuation techniques reveals strongly unstable post-buckling arising combined geometrical nonlinearities during interactive buckling global local modes—the resulting behaviour being more with decreasing hardening. finite element (FE) also devised very similar as highlighted model. results compare well terms mechanical destabilization deformation, which verifies analytical