Post-buckling behaviour of flat stiffened composite panels: Experiments vs. analysis

The paper is focused on the development of a validated procedure for modelling, by means of Finite Element tools, the post-buckling behaviour of stiffened composite flat panels subjected to compression loads. The experimental data for model validation were collected during a test campaign on two sets of CFRP flat stiffened panels. Tests are briefly described and selected experimental results, used for the validation phase, are presented. A detailed description of modelling strategies and analysis set up for post-buckling simulation is provided and some results of the sensitivity studies, which helped in fine-tuning the model of the test specimens, are reported as well. Finally, a through comparison of the model results with the experimental data is presented and commented. The final validation is accomplished not only by qualitatively comparing the buckled shape of the panels numerically predicted with those observed in the experiments, but also by quantitatively evaluating the differences between predicted and measured strains and out-of-plane displacements. The comparison between numerical and experimental results highlights the substantial effectiveness of the FEM approach in predicting the structural response of the panels in terms of buckling occurrence and of their post-buckling behaviour.