Raj K. Pandey

Bio: Raj K. Pandey is an academic researcher from Indian Institute of Technology Delhi. The author has contributed to research in topics: Bearing (mechanical) & Lubrication. The author has an hindex of 19, co-authored 94 publications receiving 1303 citations. Previous affiliations of Raj K. Pandey include Banaras Hindu University & Indian Institutes of Technology.

A Dynamic Model for Vibration Studies of Deep Groove Ball Bearings Considering Single and Multiple Defects in Races

Abstract: A dynamic model is reported herein for the study of vibrations of deep groove ball bearings having single and multiple defects on surfaces of inner and outer races. Masses of shaft, housing, races, and balls are considered in the modeling. The coupled solution of governing equations of motions is obtained using Runge―Kutta method. The model provides the vibrations of shaft, balls, and housing in time and frequency domains. Computed results from the model are validated with experimental results, which are generated using healthy and defective deep groove ball bearings. Characteristic defect frequencies and its harmonics are broadly investigated using both theoretical and experimental results. Comparison of vibration spectra for the cases having single and two defects on races reveals relatively higher velocity amplitudes with two defects. Good correlations between theoretical and experimental results are observed. Authors believe that this dynamic model can be used with confidence for the study and prediction of vibrations of healthy and defective deep groove ball bearings.

Performance of Lubricated Rolling/Sliding Concentrated Contacts With Surface Textures: A Review

Abstract: Benefits of surface textures for improving the performance behaviors of tribo-contacts are being explored and established by the investigators across the globe. But the consolidated information of findings of such explorations are spread. Therefore, the objective of this paper is to summarize the information available related to the preparation of surface textures and performance outcomes in the presence of surface textures at the concentrated contacts. Mainly, recent research findings and practices followed for the study of friction, wear, lubrication, contact fatigue, vibration, and noise at the generic concentrated contacts in presence of surface textures are reviewed for current status of research in the area and outlining the future prospects.

Vibration Modeling of a Rigid Rotor Supported on the Lubricated Angular Contact Ball Bearings Considering Six Degrees of Freedom and Waviness on Balls and Races

Abstract: Nonlinear vibration analysis of angular contact ball bearings supporting a rigid rotor ispresented herein considering the frictional moments (load dependent and load independ-ent components of frictional moments) in the bearings. Six degrees of freedom (DOF) ofrigid rotor is considered in the dynamic modeling of the rotor-bearings system. More-over, waviness on surfaces of inner race, outer race, and ball are considered in the modelby representing it as sinusoidal functions with waviness orders of 6, 15, and 25. Twoamplitudes of waviness, 0.05 and 0.2lm, are considered in the investigation looking forthe practical aspects. The proposed model is validated with the experimental results byperforming the experiments. Moreover, the present model has also been validated withpublished results of researchers by incorporating needful changes in the DOF in the pro-posed model. Based on the computed results, it is observed that load dependent frictionalmoment (LDFM) significantly enhances the amplitudes of vibrations in comparison toload independent frictional moment (LIFM) irrespective to values of waviness amplitudeand waviness order. The influence of inner race waviness is relatively more on the vibra-tions in comparison to waviness of outer race and ball. Moreover, vibrations of systemenhance considerably at high amplitude of waviness, increase in the order of waviness,and at elevated operating parameters. [DOI: 10.1115/1.4005140]