Estabilidade local de painéis cilíndricos enrijecidos

Abstract

Results from primary and secondary bifurcation loads and also results from a non-linear analysis of elastic local stability of stringer stiffened cylindrical shells under axial compression are presented. The effects due to stiffeners spacing and slenderness as well as modal interaction and inicial geometric imperfections are investigated. It is shown that the use of slender stiffeners as suggested by the orthotropic theory, can lead to interaction between local and overall modes resulting in primary bifurcation loads lower than the classical critical load for the isotropic shell. It is also indicated that interaction between primary and secondary buckling modes can occur and this is, in general, a function of stiffeners slenderness and imperfection levels. The present work constitutes then a contribution towards a better understanding of the behaviour and stability of these shells. Moreover it could serve as a guideline for adequated choice of geometric parameters for design.