We have so far assumed that the bearings are stiff. A normal hydrodynamic bearing, however, has finite stiffness and damping. Also, these may not be the same in all directions. A typical model of a rotor in journal bearings is shown in Fig. 2.2.4. We need to take into account the general non-linear and anisotropic bearing stiffness/damping properties. Thus an accurate model of the entire system would become quite complex and will need advanced modeling techniques.

Fig 2.2.4 Model of a Rotor-Bearing system