Elastic instability of thin cylindrical shells: numerical and experimental investigation

Thin walled cylinders under external pressure may be affected by instability phenomena particularly dangerous when taking place in the elastic domain. Geometric imperfections caused by fabrication processes heavily influence the critical pressure. In order to investigate the relationship between the collapse mechanism and the various types of imperfections affecting this kind of structures a series of experimental tests on scale models has been carried out. The dimensional parameters of the specimens have been selected in order to keep the instability phenomenon in the elastic range. At the same time numerical calculations simulating the experimental tests have been performed by finite element method. The geometrical defects measured on the specimens were introduced in the correspondent numerical models. A good agreement was found in the comparison between experimental and numerical results.