Application of cyclic spectral analysis to gear crack assessment

With regards to the cyclostationarity of gear vibration, a novel indicator based on cyclic spectral analysis is proposed to assess localized gear damage. The cyclic spectral density of amplitude modulation and frequency modulation signals is deduced, and its properties in joint cyclic frequency-frequency domain are summarized. The ratio between the sum of cyclic spectral density magnitude along frequency axis at the cyclic frequencies of modulating frequency and 0 Hz indicates the amplitude modulation magnitude. In the analysis of gear crack simulation vibration signals, the ratio shows a monotonically increasing trend with the development of the gear crack level. It has potential to assess gearbox damage.