Modeling and Dynamic Analysis of Spherical Roller Bearing with Localized Defects: Analytical Formulation to Calculate Defect Depth and Stiffness

Abstract

Since spherical roller bearings can carry high load in both axial and radial direction, they are increasingly used in industrial machineries and it is becoming important to understand the dynamic behavior of SRBs, especially when they are affected by internal imperfections. This paper introduces a dynamic model for an SRB that includes an inner and outer race surface defect. The proposed model shows the behavior of the bearing as a function of defect location and size. The new dynamic model describes the contact forces between bearing rolling elements and race surfaces as nonlinear Hertzian contact deformations, taking radial clearance into account. Two defect cases were simulated: an elliptical surface on the inner and outer races. In elliptical surface concavity, it is assumed that roller-to-race-surface contact is continuous as each roller passes over the defect. Contact stiffness in the defect area varies as a function of the defect contact geometry. Compared to measurement data, the results obtained using the simulation are highly accurate.

Bulletin of the Polish Academy of Sciences: Technical Sciences

“…The corresponding stiffness values in the horizontal and vertical directions are 18 MN/m and 200 MN/m, respectively. The rotor is supported with a pair of spherical roller bearings which were modeled based on kinematics and Hertzian contact theory [44]. The bearings are linearized at equilibrium condition and the stiffness is calculated.…”

Research on effect of damping variation on vibration response of defective bearings

“…The damping coefficient between the ball and the raceway is not considered in Patel's bearing model, and the numerical value and calculation method of the stiffness and damping of the rotating shaft are not given. 20 Ghalamchi et al 21 roughly estimated the damping ratio of the supporting base and the rotating shaft to 5% as the damping ratio of the model. In Sawalhi's model, 22 the gear and rotor damping ratios are selected at 5% and 35%.…”

On the complexity of failure: a functional approach to vibration analysis

“…Figure 5.3 illustrates the impulse force and the corresponding response as the local bearing resonance is excited [86]. As the size of the defect increases, the disruption of the contact forces is reflected in changes in the normal and tangential converging at the bearing [66,87,88]. From this moment onwards the system dynamic behaviour changes as a consequence of the altered load distribution.…”