Summary

A model for the coupled torsional and lateral vibrations of an unbalanced rotor is developed. The equations of motion, obtained using Lagrangian dynamics, showed inertial coupling and nonlinear interaction between the rotor torsional and lateral vibrations. A softening effect of the rotor torsional stiffness has appeared. This effect and some of the nonlinear interaction effects have appeared, for the first time in this model, due to treating the torsional angle as an individual motion. Simulation results showed energetic interaction between the rotor lateral and torsional vibrations, Responses at 1X and 3X in the torsional vibration signal and 1X and 2X in the latera