Diagnostics of Rolling Element Bearings by Means of the Higuchy Fractal Dimension

In the field of rolling element bearing, the degradation of bearing health could be detected 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, namely the Higuchi fractal dimension 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.