The Effects of Helical Ribs' Number and Grid Types on the Buckling of Thin-walled GFRP-stiffened Shells under Axial Loading

The results of an experimental study on the buckling behavior of thin-walled GFRP-stiffened cylindrical shells are presented. The buckling behavior of stiffened shells, with lozenge and triangular grids, and unstiffened shells were studied under quasi-static axial loading at room temperature. The effect of the number of helical ribs and grid shapes was thoroughly investigated. During the experimental study, local skin buckling mode was observed on all specimens. Based on the findings from this work, a minimum number of stiffeners should be present in a structure in order to play an effective role in its strength. Furthermore, it was concluded that under axial loading, increasing the number of helical ribs is more effective than adding hoop rings and changing the grid types.