6. Dynamic Modeling and Analysis of Nonlinear Flexible Rotors Supported by Viscoelastic Bearings

Rotors constitute a primary part of turbomachines such as pumps, compressors, and jet engines [1–3]. To analyze the dynamic behavior of rotor systems, simple rigid body dynamic models of rotors are first developed. Rigid body models of rotors, often referred to as Jeffcott rotor models, consider the rotor system as a rigid disk or cylinder rotating around its axis and supported on viscoelastic elements representing the combined shaft and bearing stiffness and damping [4, 5]. However, flexible models of rotors consider the shaft elasticity and corresponding geometric nonlinearities. Thus, these models are more efficient to predict the nonlinear behavior of the system arising from the nonlinear elastic motion of the shaft [3, 6–8].