Transient Flexible-Rotor Dynamics Analysis: Part 1—Theory

A mathematical formulation for the analysis of the transient and steady-state flexible rotor dynamics has been developed. Newton’s Laws of Dynamics, as used here were found to be more direct and efficient than the alternate Lagrange energy approach. In addition, the influence coefficient technique, including both bending and shear flexibility of a rotor, is applied to correlate the load deflection effects between various rotor stations. The mathematical formulation considers the general nonaxisymmetric and nonsyn-chronous rotor motion which may result from the included in-phase and out-of-phase stiffness and damping functions at all bearing and rotor stations. Other rotor dynamic parameters considered are the rotor masses and mass moments of inertia and their eccentricities and misalignments. The effects of rotor drive and dissipative torque and the interaction between torsional and transverse motion are also included.