ANSYS has no module to analyze dynamics of rotor-bearing systems,
especially to calculate critical speeds. But it has element types, such as beam element
and matrix27 element, which can be modeled as stiffness, damping and mass matrix.
In this paper, BEAM4 element and MATRIX27 element are adopted to model the
shaft, rotating disks and bearings. Some ideas are presented to deal with critical speeds
calculation using ANSYS. The accuracy of the model and the solution technique have
been demonstrated by comparison with results of previous publications. Very good
agreement has been obtained.