The present study aims to investigate the effect of geometric imperfections in circular cylindrical shells on the vibration characteristics. Perfect circular shells are characterized by the presence of double shell-like modes, i.e., modes having the same frequency with modal shape shifted of a quarter of wave-length in the circumferential direction. However, in the presence of geometric imperfections, the double natural frequencies split into a pair of distinct frequencies, the splitting is proportional to the level of imperfection. In some cases, the imperfections cause an interesting phenomenon on the modal shapes, which present a strong localization in the circumferential direction. The present study has been carried out by means of a semi-analytical approach. Theoretical formulation were derived based on Sanders–Koiter thin shell theory. The analytical results have been compared with those of standard finite element analyses. The results corresponding to the analysis of modal localization are novel and can be used as a benchmark for further studies.
Modal localization in vibrations of circular cylindrical shells with geometric imperfections / Hemmatnezhad, M.; Iarriccio, G.; Zippo, A.; Pellicano, F.. - In: THIN-WALLED STRUCTURES. - ISSN 0263-8231. - 181:(2022), pp. 1-13. [10.1016/j.tws.2022.110079]