Externally Pressurized Bearings—II: Vibration Attenuators

1968 ◽  
Vol 90 (3) ◽  
pp. 614-617 ◽  
Author(s):  
D. F. Wilcock ◽  
W. E BeVier
Keyword(s):  
Frequency Response ◽  
Closed Loop ◽  
Magnetic Hysteresis ◽  
Rolling Element Bearings ◽  
High Frequencies ◽  
Gear Teeth ◽  
Hydrostatic Bearing ◽  
Performance Factors ◽  
Rolling Element ◽  
Turbine Blading

Rolling element bearings are vibration generators, and in addition are stiff, so that they transmit rotor generated noise as well to the machine frame and casing. Self-acting (hydrodynamic) bearings are also very rigid, so that they are excellent transmitters of rotor generated vibration, e.g., front gear teeth, turbine blading, or magnetic hysteresis. A typical rotor weighing 1000 lb may be supported on bearings having a stiffness of 3 × 106 lb/in., and hence will be a good vibration transmitter up to a frequency of 172 cps. Hydrostatic bearings afford an opportunity to control the bearing frequency response so that attenuation of middle and high frequencies can be secured. Analysis of the hydrostatic bearing as a closed-loop servomechanism reveals methods of designing them for attenuation without serious consequences in other performance factors. They may be used as the primary bearing, or as separate isolator bearings in conjunction with rolling element or self-acting bearings. Some examples of possible applications are discussed.

Acoustic Emission Transducers for the Vibration Monitoring of Bearings at Low Speeds

1984 ◽  
Vol 198 (2) ◽  
pp. 127-130 ◽  
Author(s):  
P D McFadden ◽  
J D Smith
Keyword(s):  
Acoustic Emission ◽  
Frequency Response ◽  
Vibration Monitoring ◽  
Rolling Element Bearings ◽  
Rolling Element ◽  
Low Speeds ◽  
Base Strain

The use of acoustic emission transducers for the vibration monitoring of rolling element bearings at low speeds is explored. The frequency response and the base strain and bending sensitivities of the transducers are shown to be important.

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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