Research on the free vibrational characteristics of isotropic coupled conical-cylindrical shells

In engineering applications, especially in the field of modern military defence, the cylindrical shells, conical shells and coupled conical-cylindrical shells are basically simplified models of many types of weapons and equipment, such as aircraft, missiles, and submarines. The study of free vibrational characteristics of cylindrical shells is comprehensive. Initially, researchers1-5 investigated cylindrical shells using classic thin shell theories such as Donnell equations, Kennard equations, Flugge equations and Sander-Koiter equations. Harari, Sandman and Laulagnet were representative scholars in the field. Rayleigh6 was a pioneer in the study of free vibrational characteristics of cylindrical shells. The literary work of Leissa7 gave general comments on the free vibrational characteristics of cylindrical shells. The free vibrational characteristics of conical shells with simply-supported boundary conditions are examined using Statistical Energy Analysis by Creenwelge.8 Talebitooti9 and Li10 analysed the free vibrational characteristics of conical shells using the Rayleigh-Ritz method. The kp-Ritz method is used to study conical shells in the work of Liew et al.11 Guo12 applied the multiple factor method to discuss the free vibration characteristics of conical shells.