Acoustic emissions (AE) are elastic waves produced in solids due to crack propagation, dislocations, impacts, friction and others. Its potential for condition monitoring has been studied for several years. For gear transmissions, some studies have highlighted AE's advantages over other techniques. However, the application of AE in gear transmissions still requires a comprehensive understanding and modeling of the generation mechanisms.
The primary source of AE in gear transmissions is asperity contacts, making it essential to understand AE behavior under rolling and sliding friction, both contact types in gear transmissions. Our study presents simplified experiments designed to independently characterize the AE produced by a cylinder moving on a plane under rolling and sliding conditions. Additionally, we have compared our experimental findings with a theoretical model from the literature.
We tested the influence of translational speed and normal force on rolling and sliding. For sliding, we observed a positive correlation between the RMS value and the translational speed. However, the normal force did not show a significant effect, which diverges from the theoretical model. For rolling, neither translational speed nor normal force demonstrated significant effects. Regarding signal characteristics, sliding friction is characterized by a continuous AE, while rolling friction primarily exhibits stochastic AE bursts. The frequencies excited for both cases suggest that abrasive wear is predominant.
Although prior research has highlighted the impact of speed and load on AE from gears, our study offers new insights into how these conditions independently influence the AE produced by rolling and sliding friction.