Faults in rolling element bearings in a gearbox have previously been simulated using a detailed model of the gears, shafts and rolling element bearings, but only a simple model of the casing supporting the bearings. This included only one low frequency (rigid body) mode of the casing on its supports, and one High frequency to represent a typical high frequency response excited by the bearing faults. For signals bandpass filtered around this resonance, the results of envelope analysis were quite similar to measured signals, but the overall spectrum comparison over a wide frequency range was poor. In this paper, much improved spectral matching has been achieved by using a finite element model of the casing to determine its response over a much wider frequency range. Results are given for localized faults in the inner race, outer race and rolling elements, but it is intended to apply the model to extended faults in the inner and outer races, where an even greater improvement in the modelling is expected.
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