Coupled bending torsional vibration of rotors using finite element

A finite element formulation of the dynamic model of a rotor-bearing system is presented. The elastodynamic model of coupled bending and torsional motions of the rotating shaft is derived using the Lagrangian approach. The model accounts for the gyroscopic effects as well as the inertia coupling between bending and torsional deformations. A reduced order model is obtained using modal truncation. The modal transformation invokes the complex mode shapes of a general rotor system with gyroscopic effects and anisotropic bearings. The reduced modal form of the dynamic model is numerically simulated, and the dynamic responses due to different excitations are obtained. (C) 1999 Academic Press.