Multiple Design Objectives in Hydrodynamic Journal Bearing Optimization

1984 ◽  
Vol 106 (1) ◽  
pp. 54-60 ◽  
Author(s):  
S. M. Metwalli ◽  
G. S. A. Shawki ◽  
M. O. A. Mokhtar ◽  
M. A. A. Seif
Keyword(s):  
Journal Bearing ◽  
Design Procedure ◽  
Oil Viscosity ◽  
Novel Approach ◽  
Design Variables ◽  
Loss Maximum ◽  
Hydrodynamic Journal Bearing ◽  
Bearing Design ◽  
Maximum Minimum ◽  
Selection Of

A novel approach is presented to optimize the finite journal bearing performance under steady loading conditions. Closed form expressions representing the behavior of the bearing as explicit functions of the design variables are utilized. Different competing objectives are assumed to suit various design applications. A method of multiplying objectives and raising to different exponents has been adopted. The basic competing objectives are minimum power loss, maximum-minimum film thickness, minimum side leakage, minimum temperature rise, and minimum bearing size. A journal bearing design procedure for optimum performance is thus devised for the selection of optimum bearing length, clearance, and oil viscosity. A numerical example is also presented.

Optimum Design of Hydrodynamic Journal Bearings

1969 ◽  
Vol 91 (3) ◽  
pp. 516-521 ◽  
Author(s):  
A. Seireg ◽  
H. Ezzat
Keyword(s):  
Journal Bearing ◽  
Journal Bearings ◽  
Automated System ◽  
Optimal Programming ◽  
Programming Techniques ◽  
Design Systems ◽  
Hydrodynamic Journal Bearing ◽  
Bearing Design ◽  
Lubricant Viscosity ◽  
Selection Of

This paper presents an automated system for the selection of the length, clearance, and lubricant viscosity which optimize the performance of a hydrodynamic journal bearing, under specified values or ranges of load and speed. The study illustrates the feasibility of applying optimal programming techniques for the development of bearing design systems.

Numerical Analysis of Static Characteristics of Herringbone Grooved Hydrodynamic Journal Bearing

2011 ◽  
Vol 105-107 ◽  
pp. 2259-2262
Author(s):  
Han Ting Zhu ◽  
Qian Ding
Keyword(s):  
Journal Bearing ◽  
Normal Pressure ◽  
Differential Method ◽  
Static Characteristics ◽  
Load Carrying ◽  
Significant Performance ◽  
Hydrodynamic Journal Bearing ◽  
The Stability ◽  
Spiral Angle ◽  
Selection Of

By means of the finite differential method, the Reynolds equation is solved and the static characteristics of herringbone grooved hydrodynamic journal bearing are numerically analyzed by presenting the circumferential and axial pressures. The influences of parameters such as the eccentricity, width-diameter ratio of bearing, spiral angle, depth and number of grooves, on the static characteristics of herringbone grooved bearing are discussed. The results indicate that the normal pressure of oil film and the load carrying capacity as well, of herringbone grooved bearing will decrease with the increase of groove number and depth. On the other hand, as the pressure distributes in wider area in the circumferential direction, the stability of bearing can be improved. In consideration of these two aspects, the optimal groove number is 8-12, and the selection of depth and screw angle of grooves should also be chosen carefully to obtain the significant performance of herringbone grooved bearing.

An Analysis of the Steady State and Dynamic Characteristics of a Spherical Hydrodynamic Journal Bearing

1989 ◽  
Vol 111 (3) ◽  
pp. 459-467 ◽  
Author(s):  
P. S. Leung ◽  
I. A. Craighead ◽  
T. S. Wilkinson
Keyword(s):  
Steady State ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Axial Forces ◽  
Design Charts ◽  
Spherical Surfaces ◽  
Recent Developments ◽  
Hydrodynamic Journal Bearing ◽  
Bearing Design ◽  
Steady State Performance

With recent developments in N. C. manufacturing processes it is relatively straightforward to produce a journal bearing with spherical surfaces. Such a bearing offers two main advantages over a conventional bearing: it can tolerate much larger misalignment and it can resist axial forces. In this paper, the steady state performance of a spherical journal bearing is studied by using a finite bearing theory. The dynamic characteristics of the bearing are represented by eight displacement and velocity force coefficients and the boundary of bearing stability is determined. The effect of superlaminar flow upon the bearing performance is also studied, and typical bearing design charts are provided. In comparison, the behavior of the spherical journal bearing is found to be similar to that of an equivalent cylindrical bearing.

Hydrodynamic journal bearing lubricated with a ferrofluid

2017 ◽  
Vol 69 (5) ◽  
pp. 754-760 ◽  
Author(s):  
Nimeshchandra S. Patel ◽  
Dipak Vakharia ◽  
Gunamani Deheri
Keyword(s):  
Design Methodology ◽  
Journal Bearing ◽  
Magnetic Bearing ◽  
Point Of View ◽  
Content Type ◽  
Test Conditions ◽  
Hydrodynamic Journal Bearing ◽  
Bearing Design ◽  
Set Up ◽  
Bearing System

Purpose This paper aims to investigate the performance of a ferrofluid-based hydrodynamic journal bearing system. Design/methodology/approach This paper presents a new design of ferrofluid-based hydrodynamic journal bearing. An experimental set-up consisting of a magnetic shaft along with a brass bearing was modified and developed. A permanent magnet was used to make the selected shaft material magnetic. The load and speed were varied to conduct the analyses for different test conditions. Findings The paper provides information about a design of ferrofluid-based journal bearing and its improved performances. For moderate to higher loads at different shaft speeds, it was found that because of the magnetization effect, the maximum film pressure in case of a ferrofluid lubricant increased up to approximately 60 per cent, compared with that of the conventional lubricant-based journal bearing system. Besides, the temperature rise was found smaller for ferrofluid lubricants, thus making the system cooler while running. Originality/value This paper offers a new design of magnetic bearing system for the experimental analysis by utilizing a magnetic shaft with a non-magnetic bearing. The present ferrofluid-based bearing design is less complicated from manufacturing point of view.

Optimum Journal Bearing Parameters for Minimum Rotor Unbalance Response in Synchronous Whirl

1982 ◽  
Vol 104 (2) ◽  
pp. 339-344 ◽  
Author(s):  
R. B. Bhat ◽  
J. S. Rao ◽  
T. S. Sankar
Keyword(s):  
Optimal Design ◽  
Optimization Techniques ◽  
Oil Viscosity ◽  
Hydrodynamic Bearings ◽  
Unbalance Response ◽  
Design Variables ◽  
Tilting Pad ◽  
Bearing Design ◽  
Stiffness And Damping ◽  
Lower Limits

Optimization techniques are employed to design hydrodynamic bearings for minimum unbalance response of rotors in synchronous whirl. The analysis for the unbalance response considers the effects of direct and cross coupled coefficients of stiffness and damping in the bearings. A parametric study of the unbalance response is carried out to show the influence of bearing parameters on the response and to demonstrate the merits of applying optimization techniques in bearing design. The bearing parameters optimized are the diameter, clearance, and the oil viscosity. In addition to setting upper and lower limits on the foregoing design variables, the Sommerfeld number is also constrained to be within a certain range for the operational speeds of the rotor. The quantity minimized is the maximum unbalance response of the rotor in the operational speed range. Plain cylindrical, grooved, elliptical, and four shoe tilting pad type bearings are considered in the optimal design of the rotor bearing system. The results indicate that an optimal design of hydrodynamic bearings can reduce the unbalance response of rotors.

scholarly journals Effects of Tilting Pad Journal Bearing Design Parameters on the Pad-Pivot Friction and Nonlinear Rotordynamic Bifurcations

2020 ◽  
Vol 10 (16) ◽  
pp. 5406
Author(s):  
Sitae Kim ◽  
Sangwon Byun ◽  
Junho Suh
Keyword(s):  
Journal Bearing ◽  
Design Parameters ◽  
Stribeck Curve ◽  
Nonlinear Properties ◽  
Design Variables ◽  
Mass Eccentricity ◽  
Tilting Pad ◽  
Bearing Design ◽  
Set Up ◽  
Tilting Pad Journal Bearing

This study numerically analyzes and investigates the effects of the bearing design parameters of a tilting pad journal bearing (TPJB) on the pad-pivot friction-induced nonlinear rotordynamic phenomena and bifurcations. The bearing parameters were set to the pad preload, pivot offset, spherical pivot radius, and bearing length to diameter (L/D) ratio. The Stribeck curve model (SCM) model was applied at the contact surface between the pad and the pivot, which varied to the boundary-mixed-fluid friction state depending on the friction condition. The rotor-bearing model was set up with a symmetrical five-pad TPJB system supporting a Jeffcott type rigid rotor. The fluid repelling force generated in the oil film between each pad and the shaft was calculated using a finite element method. The simulation recurrently conducted the transient numerical integration to obtain the Poincaré maps and phase states of the journal and pad with various bearing design variables, then the nonlinear properties of each condition were analyzed by expressing the bifurcation diagrams. As a result, the original findings of this study are: (1) The pad preload and pivot offset significantly influenced the emergence of Hopf bifurcations and the associated limit cycles. In contrast, (2) the pivot radius and L/D ratio contributed relatively less to the friction-induced instability. Resultantly, (3) all the effects diminished when the rotor operated under the larger mass eccentricity of the disc.

Analytical and Experimental Study of Externally Pressurized Air Lubricated Journal Bearings

1962 ◽  
Vol 84 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Jason R. Lemon
Keyword(s):  
Journal Bearing ◽  
Design Parameters ◽  
Radial Clearance ◽  
Proper Selection ◽  
One Dimensional ◽  
Supply Pressure ◽  
Bearing Stiffness ◽  
Bearing Design ◽  
Gas Journal Bearing ◽  
Selection Of

A simplified analysis for calculating the characteristics, such as stiffness, flow, and load of an externally pressurized gas journal bearing, is obtained through a standard one-dimensional flow approach altered to take into account the effect of circumferential pressure variations. From this analysis, it is revealed that bearing stiffness has an optimum which, it is further shown, can be chosen through a proper selection of bearing design parameters, such as radial clearance, upstream resistor, and supply pressure. As the analysis is developed each assumption is experimentally verified. The final predictions of the analysis are also verified. It is felt that the analysis is sufficiently simple to allow comparison of many different bearing configurations, while sufficiently complete to compare very well against experimental measurements in all respects. A comparison is made between the recessed and nonrecessed bearing.

Color Trend Analysis using Machine Learning with Fashion Collection Images

2021 ◽  
pp. 0887302X2199594
Author(s):  
Ahyoung Han ◽  
Jihoon Kim ◽  
Jaehong Ahn
Keyword(s):  
Machine Learning ◽  
Trend Analysis ◽  
Image Data ◽  
Fashion Industry ◽  
Color Palette ◽  
Web Scraping ◽  
Design Variables ◽  
Sales Organizations ◽  
Fashion Designers ◽  
Selection Of

Fashion color trends are an essential marketing element that directly affect brand sales. Organizations such as Pantone have global authority over professional color standards by annually forecasting color palettes. However, the question remains whether fashion designers apply these colors in fashion shows that guide seasonal fashion trends. This study analyzed image data from fashion collections through machine learning to obtain measurable results by web-scraping catwalk images, separating body and clothing elements via machine learning, defining a selection of color chips using k-means algorithms, and analyzing the similarity between the Pantone color palette (16 colors) and the analysis color chips. The gap between the Pantone trends and the colors used in fashion collections were quantitatively analyzed and found to be significant. This study indicates the potential of machine learning within the fashion industry to guide production and suggests further research expand on other design variables.

Development of a Performance-Related Framework for Asphalt Mixture Design for the Illinois Tollway

2021 ◽  
pp. 036119812110148
Author(s):  
Behnam Jahangiri ◽  
Punyaslok Rath ◽  
Hamed Majidifard ◽  
William G. Buttlar
Keyword(s):  
Asphalt Mixture ◽  
Field Performance ◽  
Compact Tension ◽  
T Test ◽  
Novel Approach ◽  
Final Adjustment ◽  
Development And Validation ◽  
High Degree ◽  
Selection Of

Various agencies have begun to research and introduce performance-related specifications (PRS) for the design of modern asphalt paving mixtures. The focus of most recent studies has been directed toward simplified cracking test development and evaluation. In some cases, development and validation of PRS has been performed, building on these new tests, often by comparison of test values to accelerated pavement test studies and/or to limited field data. This study describes the findings of a comprehensive research project conducted at Illinois Tollway, leading to a PRS for the design of mainline and shoulder asphalt mixtures. A novel approach was developed, involving the systematic establishment of specification requirements based on: 1) selection of baseline values based on minimally acceptable field performance thresholds; 2) elevation of thresholds to account for differences between short-term lab aging and expected long-term field aging; 3) further elevation of thresholds to account for variability in lab testing, plus variability in the testing of field cores; and 4) final adjustment and rounding of thresholds based on a consensus process. After a thorough evaluation of different candidate cracking tests in the course of the project, the Disk-shaped Compact Tension—DC(T)—test was chosen to be retained in the Illinois Tollway PRS and to be presented in this study for the design of crack-resistant mixtures. The DC(T) test was selected because of its high degree of correlation with field results and its excellent repeatability. Tailored Hamburg rut depth and stripping inflection point thresholds were also established for mainline and shoulder mixes.

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