A dynamic model for simulating vibration response of ball bearings with extended outer race defects for precise spall size estimation

Abstract

A dynamic model for a ball bearing with an extended outer race defect has been proposed in this paper with an aim of precise fault size estimation. Both the varying stiffness and impact force excitation mechanisms have been incorporated. Besides, the continuously changing contact film damping and, the load zone and the resulting load distribution, are taken into account to accurately obtain the vibration response curve. The impulse force train due to impacts near the entry and the exit edges are also modelled and studied along with other important dynamic characteristics of the rotor bearing system under different operating conditions and defect parameters. The effects of different defect depth and its location, radial load, and shaft speed have been investigated. The theoretical findings were successfully validated using experimental results. The simulated results agree well with the actual vibration response of the defective bearing. Defects of five different sizes were diagnosed in light of the proposed method. A very good resemblance between the actual and the estimated values were achieved with a maximum error of 4.88%, corresponding to the smallest defect.