Remote Detection of Bearing Fatigue Spalls via the Dynamic Response of Bearings on the Same Shaft

Abstract

Turbine engine bearing failures are the leading mechanical cause of class-A failures. The most common mode of bearing failure in turbine engine applications is fatigue spalling. This paper describes a sensor capable of monitoring multiple bearings on a common shaft for the presence of fatigue spalls. Experimental data is presented demonstrating the ability of a single sensor installed on one bearing to detect spalls in other bearings sharing a shaft with the instrumented bearing. If adaptable to turbine engine applications, this monitoring approach would provide valuable benefits. Main shaft bearings located in inaccessible regions of the engine, or in regions too hot for sensor survival, could be remotely monitored by sensors mounted in accessible or cold regions. The technologies described may also be useful in other aircraft applications, such as auxiliary power units, generators, and gearboxes.