A Novel Approach for Continuous Acoustic Emission Monitoring on Rotating Machinery Without the Use of Slip Ring

The acoustic emission (AE) technique is a powerful nondestructive tool for health monitoring of structures and mechanical components, especially due to its sensitivity to capture high frequency signals, which are associated with the early stages of damage development and evolution. The aim of the present work is twofold. The first is the evaluation of a new concept of transducer mounting on rotating structures without the use of the expensive solution of the slip ring. The new concept is realized in a single stage in-house built gearbox setup. The second is the evaluation of the potential of the acquired with the new concept AE signals in distinguishing between different types of artificially induced damage on the gears. Run-in tests were carried out to study the effect of gear damage on the AE recordings. The acoustic emission signature of the healthy gears is first acquired. Then artificial defects are seeded and the acquisition is repeated. The AE signals are analyzed, and their root-mean-square values are calculated. The capability of the new approach of AE acquisition in discriminating between different loading and damage states is shown and discussed. Interesting findings on the effect of the oil temperature on AE recordings only speculated theoretically so far are also presented.