Discussion on Diagnosis of Surface Failure of Roller Using Wavelet Transform : Observation of Dynamic Behavior due to Pitting and Spalling Failures

In this paper, the wavelet transform was applied to diagnose the surface failures of rollers. The loading strain during a rotation of roller was analyzed using the wavelet transform. For pitting failure, the fatigue test was conducted using a two-cylinders testing machine. The occurring position of a large pit could be detected by the wavelet map of the loading strain, while it was difficult to detect the occurring position of a small pit. The roller with a groove was used to investigate the dynamic behavior due to spailing failure. The position of the groove could not be detected, but the intensity of the wavelet map was stronger after the groove contacted with the mating roller. From these results, it could be considered that the surface failure mode can be distinguished by the wavelet map, since the patterns on the wavelet maps between pitting failure and spalling failure were different from each other.