1. Achintya Choudhury Bhartiya Skill Development University Jaipur India
STUDIES ON VIBRATION ANALYSIS OF ROLLING ELEMENT BEARINGS WITH LOCALIZED DEFECTS
Achintya Choudhury
Bhartiya Skill Development University
Jaipur India

2. Rolling Element Bearings
Bearings are highly engineered, precision-made components that enable machinery to move at extremely high speeds and carry remarkable loads with ease and efficiency.
Bearings are found in applications ranging from small hand-held devices to heavy duty industrial systems.

3. Bearing Defects Localized defects Cracks Pits Spalls
Cause : Fatigue on rolling surfaces
Distributed defects
Surface Waviness
Misaligned races
Off-size rolling elements
Cause : Manufacturing errors, Wear

4. Localized defects in bearing elements
Applied Load IR
Load Zone OR
REs

5. Vibration Signal Processing
1.Time-domain approach
2. Freq.-domain approach
3. TF domain approach
Stationary Signals
Non-Stationary Signals

6. Two Studies
Extraction of diagnostic features from a noisy signal using a coupled method of wavelet transform and FFT analysis
Detection of localized defects on different bearing elements under dynamic loads

7. Vibratory Model of Bearing
Governing equations: =
Excitation vector with excitations due to defects on bearing elements

8. yf ybs yq nt Block Diagram for Generation of Simulated Signal
= Impulses due to defects
ybs
= Response function for bearing vibratory elements yq nt
= Radial load
= Additive noise

9. fb fc Frequency B – spline Wavelet m = Integer Order
= Frequency bandwidth fc
= Central frequency

10. Flowchart for Defect Detection

11. Detection of Inner Race Defect
Vibration response of NJ305 bearing with defect on the
inner race at 45 Hz (a) Without noise (b) with noise level
Wavelet coefficients of the noisy vibration signal
Retained Wavelet coefficients over the threshold level
Maximum Wavelet coefficients
Frequency spectrum of retained
Wavelet coefficients
Peaks at inner race defect freq.
with sidebands at shaft freq.

12. Experimental setup

13. Defect Detection from Experimental Signal

14. Dynamic Load on Bearing
Applied Load
Applied Load
Static Load
Harmonic Load
Load Zone
Random Load

15. Dynamic Load on Bearing
Modulation caused by dynamic load often results in additional spectral components
Load Zone

16. Signal Analysis Simulated Signal in time domain
Signal is high pass filtered to remove low frequency disturbances
High pass filtered signal is band-pass filtered around a prominent resonant frequency
Envelope detection using Hilbert Transform

17. Signal Analysis
Spectrum of Vibration response for Outer race defect with harmonic load
Spectrum of Vibration response for Inner race defect with harmonic load
Spectrum of Vibration response for Roller defect with harmonic load
Spectrum of Vibration response for Inner race defect with random load

18. Experimental Set-up

19. High pass filtered Signal Band-pass filtered Signal
Experimental Results
Raw Signal
(a) Time (b) Frequency
High pass filtered Signal
(c) Time (d) Frequency
Band-pass filtered Signal
(e) Time (f) Frequency

20. Experimental Results Envelope in time domain
Spectrum for outer race defect
Envelope in time domain
Spectrum for Inner Race defect

21. Theoretical Vs. Experimental Spectra for Outer Race Defect
(b)
(b)
(c)
(c)
Frequency spectra for NJ 305 bearing with outer race defect at 2840 r.p.m, W = N; and (a) Ah = 0 (b) Ah = W (c) Ah = 2W

22. Theoretical Vs. Experimental Spectra for Inner Race Defect
(b)
(b)
(c)
(c)
Frequency spectra for NJ 305 bearing with inner race defect at 2975 r.p.m, W = N and (a) Ah = 0 (b) Ah = W (c) Ah = 2W

23. Theoretical Vs. Experimental Spectral Components for Inner Race Defect

24. Publications from these studies
1. Paliwal D., Choudhury A. and Govardhan T., Detection of Bearing Defects from Noisy Vibration Signals using A Coupled Method of Wavelet Analysis followed by FFT Analysis, Journal of Vibration Engineering & Technologies, vol. 5, no. 1, 2017, pp
Govardhan T., Choudhury A. and Paliwal D., Vibration analysis of a rolling element bearing with localized defect under dynamic radial load, Journal of Vibration Engineering & Technologies, vol. 5, no. 2, 2017, pp
Govardhan T. and Choudhury A., Fault Diagnosis of Dynamically Loaded Bearing with Localized Defect Based on Defect-Induced Excitation, Journal of Failure Analysis and Prevention, Vol. 19, no. 3, 2019, pp 844 – 857.

25. Thank you