Correlation between features of acoustic emission signals and mechanical wear mechanisms

The recognition of wear mechanisms is important for effective maintenance of dynamic machinery, because the selection of an appropriate maintenance solution is dependent on the particular mechanism of wear that occurs at the frictional interface. To permit the recognition of wear mechanisms by means of an acoustic emission (AE) monitoring technique, the features of AE signals generated during adhesive wear and during abrasive mechanical wear were examined. For adhesive wear, friction and wear experiments were conducted by using a micro-sliding friction tester of the pin-on-block type with various combinations of pure metals that showed different adhesion forces. For abrasive wear, the experiments were conducted by rubbing an iron pin on emery papers with various grain sizes. AE signal waveforms generated in each wear mechanism were recorded and a frequency analysis was performed. AE signals detected during adhesive wear showed a large peak in the high-frequency region, whereas AE signals detected during abrasive wear showed a few peaks in the low-frequency region. These results permit the recognition of wear mechanisms by the AE technique.

► In adhesive wear, the amount of transfer influences the amplitude of detected AE signals.
► In adhesive wear, the frequency peak of the AE signals occurs at around 1.1 MHz.
► In abrasive wear, the size of abrasive grains influences the amplitude of detected AE signals.
► In abrasive wear, the frequency peaks are distributed in the region from 0.25 to 1 MHz.
► The mechanisms of wear can be recognized from the features of the AE frequency spectrum.