Dynamic Behavior of Reinforced Cylindrical Shells in a Vacuum and in a Fluid

Abstract

Abstract The vibrations of an infinite cylindrical shell reinforced with periodically spaced septa and stiffening rings are studied in a vacuum and in a fluid medium. Lagrange equations are used to derive the dynamic equations; the fluid reaction is obtained from the solution of the wave equation. The solution gives the dynamic characteristics of the shell, the amplitude of forced vibration, and the sound field generated thereby. The theory can be extended to shells embodying complex stiffening structures and load distributions. Certain features of the fluid reaction suggest interesting applications: Its inertial component becomes extremely large under certain conditions, thus tending to eliminate some modes of vibration; also, the resistive, i.e., damping, component may vanish for certain modes, which therefore do not radiate any sound.