Study on 3D Shape Optimization for Hydrodynamic Journal Bearing Using Goal Attainment Multi-Objective Function

2013 ◽  
Vol 319 ◽  
pp. 505-509 ◽  
Author(s):  
Xiao Ping Pang ◽  
Jin Chen
Keyword(s):  
Film Thickness ◽  
Shape Optimization ◽  
Goal Attainment ◽  
Journal Bearing ◽  
Load Capacity ◽  
Axial Direction ◽  
Three Dimensions ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Hydrodynamic Journal Bearing

This paper is focused on multi-objective optimization to find the best performance related to the geometrical design of the hydrodynamic journal bearing in three dimensions 3D. The mathematical model for 3D film thickness profile was driven using Fourier’s series function and axial waviness value to represent in circumferential and axial direction respectively. A Goal attainment function was used as an optimization tool with goals to minimize the power loss and side leakage and to maximize the load capacity, while the amplitude (a), number of wave (m) and Fourier's series coefficients of the general film thickness were taken as design variables subjected to several bounds and constraints. The optimized results show the cylindrical plain bearing is the best to load capacity due to changing the axial shape does not enhance the load capacity without violation of the minimum film thickness. Comparison was made between goal attainment multi-objective optimization and GA single-objective optimization. The new method for shape optimization based on 3D general film thickness is more evident than GA.

Numerical analysis of the transient wear and lubrication behaviors of misaligned journal bearings caused by linear shaft misalignment

2021 ◽  
pp. 1-17
Author(s):  
Tianyou Yang ◽  
Yanfeng Han ◽  
Yijia Wang ◽  
Guo Xiang
Keyword(s):  
Numerical Model ◽  
Film Thickness ◽  
Contact Pressure ◽  
Elastic Deformation ◽  
Journal Bearing ◽  
Fluid Pressure ◽  
Axial Direction ◽  
Wear Depth ◽  
Wear Process ◽  
Journal Misalignment

Abstract The purpose of this study is to investigate the role of the misalignment journal, caused by journal elastic deformation, on the transient wear and mixed lubrication performances using a numerical model. In the numerical model, the transient geometry lubrication clearance considering the journal misalignment, the transient elastic deformation and the transient wear depth are incorporated to evaluate the transient film thickness during wear process. The evolutions, under different external loads, of the wear depth, wear rate, elastic deformation, film thickness, fluid pressure and contact pressure are calculated by the numerical model. Furthermore, the calculated results of the misaligned journal bearing are compared with those of the aligned journal bearing. The results show that the distributions of the wear depth, film pressure and elastic deformation are asymmetric along the axial direction and the peak values of them shift toward the back end when the journal misalignment is considered. The maximum wear depth, maximum fluid pressure, maximum contact pressure and maximum elastic deformation of the misaligned journal condition are significantly larger than those of the aligned journal condition.

Finite Element Modelling and Multi-Objective Optimization of Composite Submarine Pressure Hull Subjected to Hydrostatic Pressure

2019 ◽  
Vol 953 ◽  
pp. 53-58 ◽  
Author(s):  
Elsayed Fathallah
Keyword(s):  
Hydrostatic Pressure ◽  
Parametric Design ◽  
Epoxy Composite ◽  
Load Capacity ◽  
Optimization Process ◽  
Valuable Insight ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Optimized Model ◽  
Better Than

Excellent mechanical behavior and low density of composite materials make them candidates to replace metals for many underwater applications. This paper presents a comprehensive study about the multi-objective optimization of composite pressure hull subjected to hydrostatic pressure to minimize the weight of the pressure hull and maximize the buckling load capacity according to the design requirements. Two models were constructed, one model constructed from Carbon/Epoxy composite (USN-150), the other model is metallic pressure hull constructed from HY100. The analysis and the optimization process were completely performed using ANSYS Parametric Design Language (APDL). Tsai-Wu failure criterion was incorporated in the optimization process. The results obtained emphasize that, the submarine constructed from Carbon/Epoxy composite (USN-150) is better than the submarine constructed from HY100. Finally, an optimized model with an optimum pattern of fiber orientations was presented. Hopefully, the results may provide a valuable insight for the future of designing composite underwater vehicles.

Empirical Treatment of Hydrodynamic Journal Bearing Performance in the Superlaminar Regime

1970 ◽  
Vol 12 (2) ◽  
pp. 116-122 ◽  
Author(s):  
H. F. Black
Keyword(s):  
Reynolds Number ◽  
Field Equation ◽  
Experimental Work ◽  
Reynolds Equation ◽  
Pressure Field ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Theoretical Treatment ◽  
Hydrodynamic Journal Bearing

The application of a perturbation in terms of simple correlations for friction in turbulent Couette and ‘screw’ flows, together with a further empirical assumption consonant with the experimental work of Smith and Fuller (1), leads to a pressure field equation identical in form with the Reynolds equation. The load capacity of journal bearings throughout most of the superlaminar range may be represented by a single curve, and existing laminar solutions may be applied with the parameters modified by Reynolds number. The theory is compared with published experimental results, and with the most successful theoretical treatment (4). The correlations obtained confirm the adequacy of the theory to predict performance in the superlaminar régime.

Experimental Characterization and Multi-Objective Optimization of the Orbital Drilling Process of CFRP

2013 ◽  
Author(s):  
A. Sadek ◽  
A. O. Nassef ◽  
M. Meshreki ◽  
M. H. Attia
Keyword(s):  
Cutting Forces ◽  
Research Work ◽  
Axial Direction ◽  
Fiber Reinforced Polymers ◽  
Test Material ◽  
Drilling Process ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Orbital Drilling ◽  
Work Done

Defects associated with drilling of Carbon Fiber-Reinforced Polymers (CFRPs) are of major economic and safety concerns for aerospace manufacturers. One of the most critical defects associated with drilling of CFRP laminates is delamination of layers which can be avoided by keeping the drilling forces below some threshold levels. Orbital Drilling (OD) is an emerging drilling process that exhibits lower cutting forces and temperatures, easier chip removal, higher produced surface quality, longer tool life, and a high possibility for dry machining. The OD process is featured by cyclic engagement and disengagement between the tool and the workpiece whereby a considerable part of the work done by the tool is directed towards the tangential direction while the work done in the axial direction is reduced. This reduces the risk of delamination at the exit. The objective of this research work is to investigate the effect of the OD process key parameters with respect to the produced hole attributes (surface roughness, delamination, and hole accuracy), as well as the cutting forces and temperatures. All the OD tests were performed under dry conditions using a four-flute 6.35 mm end-mill. The cutting forces were recorded using a 3-component dynamometer Kistler 9255B and cutting temperatures were measured using a FLIR ThermoVision A20M Infrared camera at the holes exit. A full factorial design of the experiment was used whereby the feeds varied from 60 to 360 mm/min and the speeds from 6,000 to 16,000 rpm. The test material used was a quasi-isotropic laminate comprising woven graphite epoxy prepreg. Analysis of the results showed 45% reduction in the axial force component in orbital drilling (OD), compared to conventional drilling. None of the holes produced by the entire set of experiments has experienced any entry or exit delamination. ANOVA was used to identify the significance of the controllable variables on the experimental outputs. To overcome the challenge of optimizing the competing parameters of the hole quality attributes while maximizing the productivity, an algorithm was applied by hybridizing Kriging as a meta-modeling technique with evolutionary multi-objective optimization to optimize the cutting parameters.

Inertia Effects in Hydrostatic Thrust Bearings

1961 ◽  
Vol 83 (2) ◽  
pp. 227-234 ◽  
Author(s):  
D. Dowson
Keyword(s):  
Film Thickness ◽  
Velocity Component ◽  
Load Capacity ◽  
Axial Direction ◽  
Fluid Element ◽  
Inertia Effects ◽  
Thrust Bearings ◽  
Parallel Surface ◽  
Rotating Surface ◽  
Correct Location

This paper includes the predominant inertia terms in an analysis of hydrostatic thrust bearings. The influence of centripetal accelerations on the distribution of pressure is found to be considerable. For parallel surface bearings of constant film thickness the inertia effects are found to be detrimental to load capacity. In a stepped bearing however correct location of the step can result in an increased load capacity at speed. No increase in load capacity can result from inertia effects if the step radius is less than 0.4508 of the bearing radius. A consequence of the inclusion of inertia terms in the analysis is the existence of a velocity component in the axial direction. Even in the parallel surface bearing considered a fluid element is found to move toward the rotating surface as it spirals through the clearance space.

Numerical Investigation on the Mixed Lubrication Performance of Water-Lubricated Coupled Journal and Thrust Bearings

2019 ◽  
Author(s):  
Yanfeng Han ◽  
Guo Xiang ◽  
Jiaxu Wang
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Thrust Bearing ◽  
Journal Bearing ◽  
Load Capacity ◽  
Hydrodynamic Pressure ◽  
Mixed Lubrication ◽  
Eccentricity Ratio ◽  
Thrust Bearings ◽  
Lubrication Performance

Abstract The mixed lubrication performance of water-lubricated coupled journal and thrust bearing (simplified as coupled bearing) is investigated by a developed numerical model. To ensure the continuity of hydrodynamic pressure and flow at the common boundary between the journal and thrust bearing, the conformal transformation is introduced to unify the solution domain of the Reynolds equation. In the presented study, the coupled effects between the journal and thrust bearing are discussed. The effects of the thrust bearing geometric film thickness on the mixed lubrication performance, including the load capacity, contact load and friction coefficient, of the journal bearing are investigated. And the effects of the journal bearing eccentricity ratio on the mixed lubrication performance of the thrust bearing are also investigated. The simulated results indicate the mutual effects between the journal and thrust bearing cannot be ignored in the coupled bearing system. The increasing thrust bearing geometric film thickness generates a decrease in load capacity of journal bearing. There exists an optimal eccentricity ratio of journal bearing that yields the minimum friction coefficient of the thrust bearing.

Rayleigh Step Journal Bearing, Part II—Incompressible Fluid

1969 ◽  
Vol 91 (4) ◽  
pp. 641-650 ◽  
Author(s):  
B. J. Hamrock ◽  
W. J. Anderson
Keyword(s):  
Theoretical Analysis ◽  
Film Thickness ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Single Step ◽  
Thickness Ratio ◽  
Infinite Length ◽  
One Step ◽  
Bearing Part

A theoretical analysis of the pressure distribution, load, capacity, and attitude angle for a single-step concentric as well as a multistep infinite length eccentric Rayleigh step journal bearing is performed. The results from the single-step concentric analysis indicated that the maximum load capacity is obtained when the film thickness ratio is 1.7 and the ratio of the angle subtended by the ridge to the angle subtended by the pad is 0.35. The results from the infinite length eccentric analysis indicated that one step placed around the journal was optimal. For eccentricity ratios greater than or equal to 0.2 the maximum load occurred for a bearing without a step or a Sommerfeld bearing. For eccentricity ratios less than 0.2 the optimal film thickness ratio is 1.7 while there are three optimal ratios of angle subtended by the ridge to the angle subtended by the pad of 0.4, 0.45, and 0.5 depending on whether load capacity or stability or both load capacity and stability is more important in the application being considered.

Performance Analysis of Grooved Hydrodynamic Journal Bearing with Multi-Depth Textured Surface

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
K.M Faez ◽  
S Hamdavi ◽  
T.V.V.L.N. Rao ◽  
H.H Ya ◽  
Norani M. Mohamed
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Textured Surface ◽  
Plain Bearing ◽  
Bearing Surface ◽  
Grooved Surface ◽  
Hydrodynamic Journal Bearing ◽  
Efficiency And Reliability ◽  
Capacity Performance

In recent research, theoretical studies and investigations for the textured surface of a hydrodynamic journal bearing has been widely used. This is due to the journal bearing’s performance in terms of load capacity which affects the system performance, efficiency and reliability. It has been proven that a textured surface and grooved surface have managed to improve the performance of journal bearings to some extent. In this work, the performance of a grooved hydrodynamic journal bearing has been analysed with a multi-depth textured surface. The study has been conducted using the modified Reynolds equation to numerically solve the load capacity and pressure distribution, respectively. From the results obtained, it was found that the surface complexity features on the journal bearing lowered the load capacity performance when compared to the plain bearing. The pressure, meanwhile, was distributed throughout the textured sections on the bearing surface, even though it was lower as compared to the plain bearing.

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