Elastomer Viscoelasticity Effects in Compliant Surface Bearings

1973 ◽  
Vol 95 (3) ◽  
pp. 363-371 ◽  
Author(s):  
J. Pirvics ◽  
V. Castelli
Keyword(s):  
Steady State ◽  
Pressure Distribution ◽  
Journal Bearing ◽  
Analytical Techniques ◽  
Operating Conditions ◽  
Infinite Length ◽  
Compliant Surface ◽  
Viscoelastic Effects ◽  
Bearing System

A bearing system using a compliant surface may be so constructed that the lubricant pressure distribution is either stationary or in motion relative to the elastomer. In the latter case the motion of the deformation in the elastomer introduces viscoelastic effects which can be important at conventional bearing velocities. This paper is concerned with the assessment of these effects. Steady state operating conditions are computed and analytical techniques presented for the infinite width slider and infinite length journal bearing.

Elastomer Inertia Effects in Compliant Surface Bearings

1973 ◽  
Vol 95 (3) ◽  
pp. 372-380 ◽  
Author(s):  
J. Pirvics ◽  
V. Castelli
Keyword(s):  
Steady State ◽  
Pressure Distribution ◽  
Journal Bearing ◽  
Analytical Techniques ◽  
Operating Conditions ◽  
Infinite Length ◽  
Inertial Effects ◽  
Inertia Effects ◽  
Compliant Surface ◽  
Bearing System

A bearing system using a compliant surface may be so constructed that the lubricant pressure distribution is either stationary or in motion relative to the elastomer. In the latter case the motion of the deformation in the elastomer introduces inertial effects which can be important at high enough bearing velocities. This paper is concerned with the assessment of these effects. Steady state operating conditions are computed and analytical techniques presented for the infinite width slider and infinite length journal bearing.

A transient analysis of the textured journal bearing considering micro and macro cavitation during an engine cycle

2017 ◽  
Vol 231 (10) ◽  
pp. 1289-1306 ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Di Zhang ◽  
Youbai Xie
Keyword(s):  
Transient Analysis ◽  
Engine Speed ◽  
Statistical Approach ◽  
Journal Bearing ◽  
Operating Conditions ◽  
Deterministic Approach ◽  
Textured Surfaces ◽  
Potential Reduction ◽  
System A ◽  
Bearing System

This paper presents a transient analysis of the textured journal bearing system. A mass-conserving model is developed to consider the combined effects of the inter-asperity cavitation and the macroscopic cavitation between two rough textured surfaces. In this model, the inter-asperity cavitation induced by the roughness is considered by the statistical approach (the classic flow factor methodology), while the deterministic approach is used to deal with the macroscopic cavitation induced by textures and macroscopic geometry. Moreover, the system of discretized equations for this model is unconstrained by reformulating the cavitation conditions, which is in favor of improving the computational efficiency. Furthermore, based on the fully dynamic analysis, the present study examines the effect of different textures (dimple and groove) under the engine operating conditions. It is found that the position of journal center is changed according to the engine speed and then influences the potential reduction effects produced by texturing.

The Effect of Elastic Distortions on Journal Bearing Performance

1967 ◽  
Vol 89 (4) ◽  
pp. 409-415 ◽  
Author(s):  
J. O’Donoghue ◽  
D. K. Brighton ◽  
C. J. K. Hooke
Keyword(s):  
Exact Solution ◽  
Pressure Distribution ◽  
Elastic Deformation ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Wide Range ◽  
Constant Viscosity ◽  
Outside Diameter

This paper presents a solution to the problem of hydrodynamic lubrication of journal bearings taking into account the elastic distortions of the shaft and the bearing. The exact solution for determining the elastic deformation for a given pressure distribution around a bearing is given, together with the reiterative procedure adopted to find the pressure distribution which satisfies both the hydrodynamic and elastic requirements of the system. Results are given which have been derived for a material with a Poisson’s ratio of 0.28, but other values such as 0.33 do not incur substantial errors. The results can be applied to a wide range of operating conditions using the nondimensional group of terms suggested in the paper. The bearing is assumed to be infinite in length, and infinite in thickness. The latter assumption is shown to be valid for a particular case where the outside diameter of the bearing shell is 3.5 times the shaft diameter. A further assumption in the calculation is a condition of constant viscosity of the lubricant existing around the bearing.

Structural Damping of Self-Acting Compliant Foil Journal Bearings

1994 ◽  
Vol 116 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Hooshang Heshmat ◽  
C.-P. Roger Ku
Keyword(s):  
Journal Bearing ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Test Facility ◽  
Structural Stiffness ◽  
Structural Damping ◽  
Equivalent Viscous Damping ◽  
Compliant Surface ◽  
Wide Range ◽  
Dynamic Forces

This paper describes an experimental investigation into the dynamic characteristics of corrugated foil (bump foil) strips used in compliant surface foil journal bearings and dampers. In the experimental method described herein, a test facility with a journal supported by a compliant foil journal bearing was built. The nonrotating journal was driven by two shakers which were used to simulate dynamic forces acting on bump foil strips. The dynamic structural stiffness and equivalent viscous damping coefficients are calculated based on the experimental measurements for a wide range of operating conditions. The results are compared to the analytical predictions obtained by a theoretical model developed earlier.

Transient Dynamics of a Tilting Pad Gas Bearing System

1967 ◽  
Vol 89 (4) ◽  
pp. 499-507 ◽  
Author(s):  
V. Castelli ◽  
J. T. McCabe
Keyword(s):  
Steady State ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Degree Of Freedom ◽  
Performance Characteristics ◽  
Experimental Results ◽  
Transient Dynamics ◽  
Tilting Pad ◽  
Gas Bearing ◽  
Bearing System

A method for obtaining the performance characteristics of a rotor-tilting pad gas lubricated journal bearing system by solving the appropriate dynamics equations together with the time-transient Reynolds’ equation is outlined. Results for a 4 degree of freedom and an 18 degree of freedom system are given. Comparison with steady-state and experimental results are also discussed.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

Steady-state Security Assessment Based on K-Means Clustering Algorithm and Phasor Measurement Units

2020 ◽  
Vol 13 (4) ◽  
pp. 559-570
Author(s):  
Bassam A. Hemade ◽  
Hamed A. Ibrahim ◽  
Hossam E.A. Talaat
Keyword(s):  
Steady State ◽  
Clustering Algorithm ◽  
System Security ◽  
Phasor Measurement Units ◽  
Operating Conditions ◽  
Security Assessment ◽  
State Security ◽  
Phasor Measurement ◽  
Measurement Units ◽  
Silhouette Analysis

Background: The security assessment plays a crucial role in the operation of the modern interconnected power system network. Methods: Hence, this paper addresses the application of k-means clustering algorithm equipped with Principal Component Analysis (PCA) and silhouette analysis for the classification of system security states. The proposed technique works on three principal axes; the first stage involves contingency quantification based on developed insecurity indices, the second stage includes dataset preparation to enhance the overall performance of the proposed method using PCA and silhouette analysis, and finally the application of the clustering algorithm over data. Results: The proposed composite insecurity index uses available synchronized measurements from Phasor Measurement Units (PMUs) to assess the development of cascading outages. Considering different operational scenarios and multiple levels of contingencies (up to N-3), Fast Decoupled Power Flow (FDPF) have been used for contingency replications. The developed technique applied to IEEE 14-bus and 57-bus standard test system for steady-state security evaluation. Conclusion: The obtained results ensure the robustness and effectiveness of the established procedure in the assessment of the system security irrespective of the network size or operating conditions.

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