This project, sponsored by the Office of Naval Research, integrates oil and vibration analysis to develop a more complete diagnostic and prognostic model for monitoring bearing degradation and performance while inside a vehicle's differential. The results of this project could be used to optimize repair schedules and minimize the risk of catastrophic failure of machine components for military personnel during a mission through condition-based maintenance. Each test bearing is first introduced with an outer race fault. The fault's degradation is then accelerated by running the bearing under overloaded conditions in the boundary lubrication regime. Accumulated damage to the bearing is characterized in a clean, low-noise environment before being implemented into the differential for in-situ testing. Dynamic characterization of the designed test machines were performed by long runs spanning multiple hours under rated conditions to determine any wear-in effects and ramp-up tests to distinguish order-based bearing frequencies and structural resonances. Modal analyses were performed on the static system to provide additional evidence of structural resonances within the machines. This paper will discuss the design challenges and solutions for creating a test bed to monitor bearings in accelerated-degradation conditions and in noisy environments, such as the differential. Results of run-to-failure data and analysis will also be presented.
