Effect of rotational speed fluctuations on the dynamic behaviour of rolling element bearings with radial clearances

2006 ◽  
Vol 48 (8) ◽  
pp. 809-829 ◽  
Author(s):  
A.N. Lioulios ◽  
I.A. Antoniadis
Keyword(s):  
Rotational Speed ◽  
Dynamic Behaviour ◽  
Rolling Element Bearings ◽  
Rolling Element ◽  
Speed Fluctuations

Stabilizing Effects of Speed Fluctuations on the Dynamic Response of Rolling Element Bearings With Radial Clearances

2005 ◽  
Author(s):  
A. N. Lioulios ◽  
I. A. Antoniadis
Keyword(s):  
Theory Of Elasticity ◽  
Contact Forces ◽  
Radial Clearance ◽  
Rolling Element Bearings ◽  
Governing Parameter ◽  
Frequency Distributions ◽  
Rolling Element ◽  
Stabilization Effect ◽  
Speed Fluctuations ◽  
Varying Compliance

A horizontal balanced rotor supported on ball bearings with radial internal clearance, subjected to rotational speed fluctuations is modeled. The dynamic model takes under consideration contact forces derived by the hertzian theory of elasticity between the balls and the races, the effect of varying compliance, the internal radial clearance and the rotor’s speed fluctuations. The effect of variation in speed fluctuations is examined for periodic, unstable periodic and chaotic responses with the use of frequency distributions, higher order Poincare maps, and Lyapunov exponents. All results presented show a dominant stabilization effect of the speed fluctuations to the system behavior. From the analysis performed, it is concluded that even a minimum fluctuation of the rotor speed may result to major changes of the system dynamics, indicating that speed fluctuations of the rotor are a governing parameter to the dynamic behavior of the system.

scholarly journals Autocorrelation Ensemble Average of Larger Amplitude Impact Transients for the Fault Diagnosis of Rolling Element Bearings

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4740
Author(s):  
Lei Hu ◽  
Yuandong Xu ◽  
Fengshou Gu ◽  
Jing He ◽  
Niaoqing Hu ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Vibration Signal ◽  
Ensemble Average ◽  
Rolling Element Bearings ◽  
Ensemble Averaging ◽  
Critical Elements ◽  
Phase Errors ◽  
Rolling Element ◽  
Zone Centre ◽  
Speed Fluctuations

Rolling element bearings are one of the critical elements in rotating machinery of energy engineering systems. A defective roller of bearing moves in and out of the load zone during each revolution of the cage. Larger amplitude impact transients (LAITs) are produced when the defective roller passes the load zone centre and the defective area strikes the inner or outer races. A series of LAIT segments with higher signal to noise ratio are separated from a continuous vibration signal according to the bearing geometry and kinematics. In order to eliminate the phase errors between different LAIT segments that can arise from rotational speed fluctuations and roller slippages, unbiased autocorrelation is introduced to align the phases of LAIT segments. The unbiased autocorrelation signals make the ensemble averaging more accurate, and hence, archive enhanced diagnostic signatures, which are denoted as LAIT-AEAs for brevity. The diagnostic method based on LAIT separation and autocorrelation ensemble average (AEA) is evaluated with the datasets captured from real bearings of two different experiment benches. The validation results of the LAIT-AEAs are compared with the squared envelope spectrums (SESs) yielded based on two state-of-the-art techniques of Fast Kurtogram and Autogram.

Experimental investigation on time-domain features in the diagnosis of rolling element bearings by acoustic emission

2021 ◽  
pp. 107754632110161
Author(s):  
Aref Aasi ◽  
Ramtin Tabatabaei ◽  
Erfan Aasi ◽  
Seyed Mohammad Jafari
Keyword(s):  
Acoustic Emission ◽  
Condition Monitoring ◽  
Time Domain ◽  
Central Moment ◽  
Rolling Element Bearings ◽  
Test Rig ◽  
Acoustic Emission Sensor ◽  
Outer Race ◽  
Common Time ◽  
Rolling Element

Inspired by previous achievements, different time-domain features for diagnosis of rolling element bearings are investigated in this study. An experimental test rig is prepared for condition monitoring of angular contact bearing by using an acoustic emission sensor for this purpose. The acoustic emission signals are acquired from defective bearing, and the sensor takes signals from defects on the inner or outer race of the bearing. By studying the literature works, different domains of features are classified, and the most common time-domain features are selected for condition monitoring. The considered features are calculated for obtained signals with different loadings, speeds, and sizes of defects on the inner and outer race of the bearing. Our results indicate that the clearance, sixth central moment, impulse, kurtosis, and crest factors are appropriate features for diagnosis purposes. Moreover, our results show that the clearance factor for small defects and sixth central moment for large defects are promising for defect diagnosis on rolling element bearings.

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