Imperfection investigation of composite stiffened fuselage panels for Postbuckling analyses

Kurzfassung

Project COCOMAT is an ongoing four year European Commission project aimed at exploiting the large reserve of strength in composite structures through more accurate prediction of collapse. As part of the research program, curved stiffened composite panels have been manufactured and tested in compression. During the experiments, it was noted that the panels were highly imperfection sensitive. Imperfections in the structure contributed to variations in the postbuckling mode shape as well as the collapse load. The inability of deterministic finite element analyses to easily capture these variations means that it is difficult to match simulation with experiment. Therefore the use of stochastic finite element analyses has been proposed. In order for realistic stochastic simulations to be conducted, there is a need to investigate the actual variability and imperfections that exist in the manufactured panels. A library of imperfections and variations has been collated and the initial geometrical imperfections that exist before testing have been accounted for.