Modal analysis of a rotating multi-packet blade system

A modeling method for the modal analysis of a multi-packet blade system undergoing rotational motion is presented in this paper. Blades are idealized as tapered cantilever beams that are fixed to a rotating disc. The stiffness coupling effects between blades due to the flexibilities of the disc and the shroud are modeled with discrete springs. Hybrid deformation variables are employed to derive the equations of motion. To obtain more general information, the equations of motion are transformed into a dimensionless form in which dimensionless parameters are identified. The effects of the dimensionless parameters and the number of packets on the modal characteristics of the rotating multi-packet blade system are investigated with numerical examples.