Influência da interação entre modos e imperfeições na flambagem de cascas cilíndricas axialmente comprimidas

Abstract

Results from a non-linear analysis of circular cylindrical shells under axial compression are presented. Included in this analysis are the effects that mode coupling and initial geometric imperfections have on the non-linear buckling behaviour. It is shown, through the inspection of energy distributions, that the stabilizing membrane energy contributions are eroded substantialy during the imperfection-sensitive non-linear mode interaction that occurs in the buckling of these shells. The results of this analysis are used to validate a recently proposed linearized reduced energy model that provides theoretical lower bound estimates of reported buckling loads. Extending this analysis to advanced post-critical (post-buckling) equilibrium states, important qualitative informations were obtained and made it possible to propose a non-linear reduced energy model which seems to provide close estimates for the buckling loads with little computational effort. Finally, the theoretical results obtained with these simplified models are shown to compare favourably with experimental results, representing, unlike other procedures, simple alternative methods for calculating buckling loads.