A reduced model for nonlinear analysis and design of thin-walled structures prone to multi-modal buckling

Abstract

The Koiter method is a reduction technique based on a multi-modal quadratic asymptotic expansion of the finite element model for recovering the equilibrium path of an elastic structure prone to buckling. Its main feature is the possibility of performing an inexpensive sensitivity analysis to geometrical imperfections by including the effects of the deviations in the reduced model of the perfect structure. The method is so efficient that can be used for optimal design of slender structures, where it provides the collapse load associated to each set of design parameters taking into account the nonlinear behaviour and the worst-shape imperfection at a computational cost similar to a linearised buckling analysis.