Free vibration of thin cylindrical shells with a discontinuity in the thickness

Abstract The vibrations of cylindrical shells, consisting of two sections of different thicknesses but with a common mean radius, have been investigated. Natural frequencies and mode shapes have been determined theoretically using two types of ring finite element; some frequencies have been obtained also from a direct solution of the shell equations, satisfying all boundary conditions and the continuity conditions at the intersection of the two thicknesses. There is good agreement between frequencies derived by the two methods and with existing experimental results for a series of shells with simply-supported ends. Detailed consideration is given to the changes in natural frequency and mode shape for various modes of a shell of constant length as the ratio of the length of the thin section to the length of the thick section is varied.