Investigation on the vibration mechanisms of a rotating FG-GPLRC shaft-disk-shell combined system

Abstract

In this paper, a dynamics model of a rotating shaft-disk-shell (SDK) combined system is proposed to solve the vibration characteristics of a flexible rotor system. Unlike many previous researches that only studied shaft-disk systems, this paper simplifies the rotor into a combined structure of shaft, disk and cylindrical shell. The functionally graded graphene platelet (GPL) reinforced composites are innovatively applied in the disk to achieve the system lightweight. Timoshenko beam theory and first-order shear deformation theory are used to model the substructures. And the energy expressions of each substructure are derived based on the multi-body dynamics theory. Finally, the differential quadrature finite element method is used to discretize and reassemble the energy matrix to obtain the overall system’s motion differential equation. The model is proved to have excellent convergence and accuracy. Then the influence mechanism of GPL parameters, system geometry, etc. on the system’s coupled vibration characteristics is further explored, and important conclusions are drawn, like when the shell parameters h/R < 0.08 and l/R < 0.03, the system’s 3rd coupled natural frequency is insensitive to these parameters.