Fundamental study on early detection of seizure in journal bearing by using acoustic emission technique

AE frequency shifts to less than 0.3 MHz originate from the formation and collision of wear particles.
• A frequency shift to less than 0.3 MHz occurs at about 30% of the lifetime of the bearing before seizure.
• Early detection at about 90% of the lifetime of the bearing before seizure is possible by detecting AE signals at more than 1 MHz that originate from adhesion.
• Changes in the amplitude and in the frequency of AE signals are both essential items of information for the early detection of seizure.

In monitoring and maintaining machineries, it is extremely important to identify and quantify friction and wear phenomena, for example the progression of wear and the state of friction between sliding surfaces. Because friction and wear processes involve deformation and fracture of materials, they generate elastic stress waves that can be detected and measured as acoustic emission (AE) signals. By measuring these AE signals, it is then possible to monitor tribological processes between sliding materials in situ. To establish parameters for condition-based maintenance based on AE technique, the relationship between changes in the wear state and changes in AE signals was investigated using a high-speed grease-lubricated slide bearing. Monitoring high-frequency AE signals of more than 1 MHz that originates from adhesion is an effective way to detect early seizure in machineries.

Figure optionsDownload high-quality image (278 K)Download as PowerPoint slide