Early Detection of Fatigue Cracks in Gears by Vibration Analysis Techniques

Tests were carried out in order to compare the sensitivity of two techniques in early detecting fatigue cracks in gears, namely analysis of the time synchronous average of the demodulated acoustic emission and vibration signals, both picked up from the gear case. In the case of the vibration signal an existing technique, based on evaluation of the phase modulation of one of the tooth meshing harmonics, is further developed to increase sensitivity. The latter technique appears to be largely more sensitive, on condition that a proper frequency band is processed. (A)