Buckling identification in composite cylindrical shells with measured imperfections using a Multi-DIC method and finite element analysis

In this study, we investigated the global-local buckling phenomenon with the aid of a multi-Digital Image Correlation (DIC) technique. First, the multi-DIC technique was introduced to conduct 360-degree full-field deformation measurement of shell structures. Second, we performed the axial compression on cylindrical shells made of carbon fiber reinforced polymer (CFRP) to investigate the global-local buckling phenomenon. To confirm our experimental results, we conducted a finite element analysis of CFRP cylindrical shells with measured imperfections. In the case of a perfect shell under perfect loading, theoretically only global buckling occurs. However, manufactured cylindrical shells cannot be perfect and tend to have a few imperfections, which cause local buckling of the shell. To better confirm the experimental results, an extensive numerical analysis was performed with actual measured imperfections.