Vibration of a Spinning Cylindrical Shell With Internal/External Ring Stiffeners

The paper presents an approach to the vibration analysis of a spinning cylindrical shell with internal, symmetric, or external ring stiffeners. A modified receptance method for spinning structures is employed in this analysis. Various numerical examples are demonstrated and the results are compared with the existing data. The effects of types, numbers of stiffeners and of spin speed on the shell frequencies are extensively discussed. The results show that for no spin the ring stiffeners stiffen only then > 1 modes (n–circumferential wave number), and the stiffening effect become more significant with the increasing n number. With spin, the rings stiffen the forward modes in a way similar to the non-spin cases. The backward modes are however all stiffened by the attached rings for all n values. Among the three types of rings, on backward modes, the internal rings always have a better stiffening effect, then the symmetric and the external rings. As to the forward modes, as spinning speed increases, the external rings raise the shell’s frequencies faster than the others due to the largest centrifugal force. At last, the effects of the ring’s location, stiffness, and mass density on the frequency changes are examined. Numerical results show that the sensitivity of the shell’s frequencies to these parameters increases with the spin speed. Among the shell modes, the lower n modes are affected more by these parameters.