Vibrational Diagnosis of Defects in Bearings and Gears used in a Gearbox
• Designed a gearbox to simulate a special case of gear defect frequency being an integral multiple of bearing defect frequency
• Numerically modelled the gearbox using a lumped parameter model treating bearings and gears as lumped masses
• Validated the model by comparing its obtained features to documented results of LPM in reported literature
• Simulated the vibration response of the gearbox in three cases: healthy state, with cracked gear and with cracked bearing
• Manufactured the gearbox with alterable roller bearings and spur gears
• Conducted data acquisition and analysis in healthy state and with cracked gear
• Established through experiment in accordance with literature that a gear crack can be identified by an increase in vibration amplitude, sidebands, Hilbert transform and analysis of the residual signal
• Concluded through simulation that the bearing crack in this special case is indiscernible using the above techniques and requires the usage of Kurtosis and High Frequency Resonance Technique