Use of chaos in the diagnostics of rolling element bearings

Abstract

On-line monitoring and real-time diagnostics of rolling element bearings are complex tasks to be performed when operating conditions change continuously. In particular, real-time applications require simple and effective diagnostics tools. In the field of rolling element bearing, the most common approach is the Envelope analysis of vibration signals. The output of this analysis is the identification of bearing damage frequency components in the Envelope Spectrum of vibration signals. The degradation of bearing health could be tracked by means of suitable damage indexes. Band-Kurtosis index, that is the kurtosis value of the band-filtered signal, is often assumed. The critical point of this approach is the selection of a suitable filter band. In the paper, the use of a chaos metrics as damage indicator is described. The trend of this index is compared with the common approach of band-kurtosis indicator for an experimental case of a rolling element bearing in which the defect developed until a permanent failure.