Rotor Fault Diagnosis Utilizing Active Magnetic Bearings

Document Type


Publication Date


Publication Title

SPIE's 13th Annual International Symposium on Smart Structures and Materials


6176-09, Session 2

This paper conducts an analytical modeling effort and an experimental system design in order to assess the feasibility of utilizing active magnetic bearings (AMB) for rotor fault diagnosis. Mathematical models are developed in order to gain an understanding of the interaction between the rotor system and the AMBs (both conical and radial). The rotor system is in the form of a Jeffcott rotor, therefore, the set-up involves a rigid disk located mid-span on a flexible shaft with rigid supports (i.e., traditional ball bearings providing support). Based on the modeling results, the AMBs are located along the shaft between the ball bearings and the disk, and are designed to act as actuators (force inputs) and sensors (force and displacement responses) with the sole purpose of damage assessment through selected modal excitations of the rotor. The excitations as well as the recorded responses are both axial and radial. Again, at this point the AMBs are not expected to act as structural supports, although, future work will aim to use the AMBs as both structural supports and damage assessing actuators/sensors. The physics based models are used to define the domain for the required force inputs (i.e., the magnetic actuation signals) that excite particular system modes aimed at revealing various types of rotor damage. An important goal of this structural health monitoring procedure is the identification of disk cracks and shaft cracks due to their catastrophic and costly failure modes, especially in the aerospace field. Lastly, considering the modeling results and program requirements an experimental system design is presented.