Buckling of imperfect cylindrical shell under lateral pressure

experimental assessment methods, in the context of NPP applications as, for instance, the IRIS LWR integrated Steam Generator (SG) tubes. Design/methodology/approach: In this paper, thin shell, homogeneous and isotropic material, also tube geometric imperfections as eccentricity/ovality/welding are assumed to investigate the effects of latter on the limit pressure load in conditions for which, at present, a complete theoretical analysis was not found in literature. At Pisa University a research activity is being carried out on the buckling of thin walled metal specimen, with a test equipment (and the necessary data acquisition facility), suitable for carrying out test series on this issue, as well as numerical models implemented on the MARC FEM code, were set up. Findings: The experiments were conducted on test specimens of the same material (AISI 316) tube with and without longitudinal welding. The comparison between numerical and experimental results, for the same geometry and loading conditions, shows a good agreement between the elastic-plastic finite-element predictions and the experimental data. Research limitations/implications: The presented research results may be considered preliminary in the sense that it would be important to enlarge the statistical base of the results themselves, even if they are yet certainly meaningful to highlight the real problem, considering the relatively large variability of the geometrical imperfections also in high quality production tubes. Originality/value: From the point of view of the practical implication, besides the addressed problem general interest in industrial plant technology, it is worth to stress that straight and curved axis tubes are foreseen specifically in innovative nuclear reactors SG design Keywords: Numerical techniques