The effect of plane-symmetric mass loading on the response of ring-stiffened cylindrical shells

The present investigation is an analytical study of the in-vacuo vibrations of a simply supported, mass-loaded thin cylindrical shell which is reinforced by equally spaced ring stiffeners. Four masses are attached to each stiffening ring in a plane-symmetric fashion. The angular position of two of the masses is fixed, but that of the other two can be varied. The rotatory inertia of the masses is taken into account, but similar effects for the shell and ring stiffeners are neglected. Lagrange's equations are used to derive the dynamic equations of the shell structure and the Jacobi iteration method is employed to find the natural frequencies and corresponding mode shapes. Results are given for various values and angular position of the masses to show the effects of mass loading. When the value of the masses is allowed to become zero, the results for the ring-stiffened shell are in close agreement with those of previous investigators. Modal analysis is used to obtain the response of the structure to different types of excitation. Two types of excitation are studied: (1) a band of uniform internal pressure applied as a pulse in time, (2) a pressure wave which strikes the shell transversely. Numerical results are not presented for these two cases.Mechanical Engineering, Department o