Abstract
A study of an elastic rotor supported by two defect bearings is presented. The bearing behavior must be considered non-linear because of the defect effects. The rotor is modelled by typical beam finite element including effects such as gyroscopic effect. The dynamic behavior is analysed using an unsteady time integration procedure. A modal technique is used to reduce the number of degrees of freedom. Results show that the bearing defects introduce supplementary critical speeds. The linear approach is unable to show the supplementary critical speeds which are obtained only by using non linear analysis.