Postbuckling behavior of a pressurized stiffened composite panel - Part II: Numerical analysis. Effect of the geometrical imperfections

Numerical simulations of the experimental tests performed with a pressurized composite stiffened panel are presented in this paper. As a consequence of the high slenderness of this structural typology, pressure caused the panel to enter the postbuckling regime. Previous experimental tests showed that the panel had a large safe postbuckling range, the experimental collapse pressure being over four times the first buckling load. Due to the relevant influence of the geometric imperfections on the global response, a procedure for taking into account actual imperfections in the development of the models is proposed. This procedure can be used as a tool to facilitate the modeling of the actual geometry of the panel, mainly the zone of the skin located between the stringers. A satisfactory agreement with experimental results has been reached using the proposed procedure.