Amplitudes of components in vibration spectra of rolling bearings with localized defects under harmonic loads

In the present work, an attempt has been made to obtain the vibration response with relative amplitudes of the spectral components for a rolling element bearing with localized defect on different elements under the action of harmonic radial load. The bearing has been assumed as a multi-degree-of-freedom system, and the frequency of harmonic load has been considered to be the shaft frequency. The vibration spectra have been obtained using envelope detection technique. The modulating effects of the harmonic load has resulted in additional sidebands at shaft frequency about the components which are otherwise caused by static load for defects on the outer race and the rolling element. For inner race defect, no additional components exist because the modulating frequency is equal to the shaft frequency at which the sidebands appear even for the static load. A detailed experimental investigation has also been carried out in the present work to validate the theoretical results. The results of theoretical and experimental investigations show the amplitudes of spectral components for both the studies are of the same order and their normalized values have fair agreement between them.