The Occurrence of Painleve’s Paradox in the Motion of a Rotating Shaft

1997 ◽  
Vol 64 (4) ◽  
pp. 1008-1010 ◽  
Author(s):  
E. V. Wilms ◽  
H. Cohen
Keyword(s):  
Rotating Shaft ◽  
Painlevé’S Paradox

Bisynchronous Torsional Vibrations in Rotating Shafts

1987 ◽  
Vol 54 (4) ◽  
pp. 893-897 ◽  
Author(s):  
O. Bernasconi
Keyword(s):  
Angular Momentum ◽  
Nonlinear Term ◽  
Rotation Frequency ◽  
Longitudinal Component ◽  
Torsional Vibrations ◽  
Rotating Shaft ◽  
Rotating Shafts

In this study, the intrinsic behavior of rotating shafts with residual unbalance is considered. The longitudinal component of the angular momentum caused by synchronous precession (whirling) induces torsional vibrations with a frequency of twice the rotation frequency (bisynchronous). The nonlinear term which represents this coupling is characteristic of the asymmetrical aspect of rotating shaft kinematics. This result has been obtained analytically and confirmed experimentally.

scholarly journals Wellbore trajectory control tool seal system leakage analysis based on steady gap flow

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402093046 ◽  
Author(s):  
Lei Shi ◽  
Keqiang Wang ◽  
Ding Feng ◽  
Hong Zhang ◽  
Peng Wang
Keyword(s):  
Prediction Method ◽  
Electronic System ◽  
Contact Length ◽  
Trajectory Control ◽  
Analysis Model ◽  
Rotating Shaft ◽  
Element Analysis ◽  
Gap Flow ◽  
Total Leakage ◽  
Gap Height

Lubricant leakage will inevitably occur during the working process of wellbore trajectory control tools. Even including the lubricant compensation system, serious leakage will still cause lacks lubrication of the internal mechanical structure as well as electronic system damaged by external infiltration fluid, especially when it comes to battery sub and other electronic equipment. Seal system leakage prediction method was presented based on the assumption of steady gap flow. It is assumed that there is a constant gap between the lip seal and the rotating shaft, the gap height is determined by oil film thickness, and the length of the gap was determined by the contact analysis using the Mooney–Rivlin constitutive model. The analysis results show that the contact length between the primary seal lip and the rotary shaft is about 0.1 mm under the condition of ensuring the contact between the deputy seal lip and the rotary shaft. The overall lubricant leakage finite element analysis model was established, and the relationship between the internal lubricant pressure of the tool and the total leakage was obtained. The results of analysis indicate that under the internal pressure of 0.03 MPa, the lubricant leakage is approximately 6 mL/h, which was verified by experiments.

Analysis of the rub-impact forces between a controlled nonlinear rotating shaft system and the electromagnet pole legs

2021 ◽  
Vol 93 ◽  
pp. 792-810
Author(s):  
N.A. Saeed ◽  
Emad Mahrous Awwad ◽  
Mohammed A. EL-meligy ◽  
Emad Abouel Nasr
Keyword(s):  
Rotating Shaft ◽  
Shaft System ◽  
Impact Forces
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