Dynamic modelling for vibration analysis of a cylindrical roller bearing due to localized defects on raceways

The current study presents a multi-body dynamic model for investigating the vibration responses of a cylindrical roller bearing with localized surface defects such as dents on raceways. This model is developed with the assumptions that outer raceway is fixed in space and other elements have three degrees of freedom (DOF): two translations and one rotation. Centrifugal forces, gravity forces and slipping of the rollers are taken into account. The couplings of the Hertzian line contact deformation theory and the slice method are used to calculate all the contact forces. Local deflections due to defects are introduced into the constructed model by the time-varying deflection excitation. The equations of motion are established by the Newton-Euler method and solved by the fourth-order Runge-Kutta integration method with variable steps. Both time and frequency domains are used to analyse dynamic responses of the defective bearing. Some new components of the characteristic defect frequency can be seen from the results. The effects of time-varying surface models, different defect types and defect sizes on dynamic responses of the defective bearing are studied. An experiment is carried out to validate the proposed model. Comparison of the frequency spectrum in simulation results with that in the experiment shows reasonable qualitative agreement.