Hydrostatic bearings with multiport viscous pumps

2003 ◽  
Vol 217 (4) ◽  
pp. 333-342 ◽  
Author(s):  
H. A. Arafa ◽  
T. A. Osman
Keyword(s):  
Load Carrying Capacity ◽  
Pressure Source ◽  
Hydrostatic Bearing ◽  
Supply Pressure ◽  
Hydrostatic Bearings ◽  
Load Carrying ◽  
Viscous Pump ◽  
Bearing Stiffness ◽  
Flow Pressure ◽  
Good Agreement

An analysis of multirecess hydrostatic bearings with linear flow-pressure supply characteristics is presented. These characteristics can be obtained using either a constant supply pressure source with a laminar flow restrictor before each recess, or, as suggested in this paper, a multiport viscous pump. Analysis of the viscous pump-bearing system is made for odd numbers of recesses, and it is shown that a staggered or skip-one sequence of connection of the pump ports to the bearing recesses gives the least unbalanced reaction between the pump rotor/stator. The flow-pressure characteristics of viscous pumps with peripheral shrouded Rayleigh steps in a cylindrical configuration are derived and used to design a five-port pump to match a hydrostatic bearing. An experimental pump is designed, manufactured and tested, and the results obtained at one port show good agreement with the theoretically calculated values of pressure and flow. If this port is taken as representative of a pump, which is manufactured with higher accuracy, then the principle of having an effective multiport viscous pump is hereby validated. A simple means is suggested for making the bearing stiffness and load-carrying capacity insensitive to temperature/viscosity changes.

Experimental Investigation of Static Characteristics of a Vacuum Preloaded Aerostatic Bearing

2011 ◽  
Vol 311-313 ◽  
pp. 1012-1016 ◽  
Author(s):  
Shan Shan Liu ◽  
Han Chen ◽  
Xue Dong Chen
Keyword(s):  
Analytical Model ◽  
Carrying Capacity ◽  
Vacuum Pressure ◽  
Load Carrying Capacity ◽  
Static Characteristics ◽  
Aerostatic Bearing ◽  
Supply Pressure ◽  
Air Supply ◽  
Load Carrying ◽  
Bearing Stiffness

A vacuum preloaded circular aerostatic bearing was designed and its static characteristics were investigated experimentally. The load carrying capacity and air film thickness of the bearing were measured for different air supply pressure and vacuum pressure values. An orthogonal table was constructed to optimize the experimental measurement. Regression analysis was performed on the experimental results to obtain an analytical model of the bearing stiffness as a function of the load carrying capacity, air supply pressure and vacuum pressure. Accuracy of this analytical model in predicting static characteristics of the aerostatic bearing was validated by comparison with experimental data, and influences of the functioning parameters were also discussed.

Self-Compensated Precision Hydrostatic Rotary Bearing

2013 ◽  
Vol 662 ◽  
pp. 674-677
Author(s):  
Xiao Bo Zuo ◽  
Jian Min Wang ◽  
Zi Qiang Yin ◽  
Sheng Yi Li
Keyword(s):  
Fluid Flow ◽  
Carrying Capacity ◽  
Radial Direction ◽  
Axial Direction ◽  
Load Carrying Capacity ◽  
Hydrostatic Bearing ◽  
Supply Pressure ◽  
Load Carrying ◽  
Network Method ◽  
Precision Machines

A self-compensated hydrostatic rotary bearing is designed and manufactured. The bearing is modeled by fluid flow network method, and simulations are performed to predict the load carrying capacity. A hydrostatic bearing prototype has been tested and results show that it can achieve a stiffness of 120N/μm in radial direction and 220N/μm in axial direction under a supply pressure of 1 MPa, and its motion accuracy is 0.3μm. The designed bearing is suitable to be used in precision machines.

scholarly journals Design of steering system of a buggy

2020 ◽  
Vol 327 ◽  
pp. 03004
Author(s):  
D. Santana Sanchez ◽  
A. Mostafa
Keyword(s):  
Carrying Capacity ◽  
Steering System ◽  
Nonlinear Finite Element ◽  
Load Carrying Capacity ◽  
Dynamic Effects ◽  
Flexural Behaviour ◽  
Steering Angle ◽  
Load Carrying ◽  
And Performance ◽  
Good Agreement

The present paper discusses the design analysis and limitations of the steering system of a buggy. Many geometrical and performance characteristics of the designed steering system were considered to address the kinematic constraints and load carrying capacity of the steering elements. Ackremann geometry approach was used to assess the limiting steering angle, while Lewis bending formula with the inclusion of dynamic effects was employed to characterise the flexural properties of the rack and pinion steering system. Analytical results were numerically verified using ABAQUS/Explicit nonlinear finite element (FE) package. Good agreement has been achieved between analytical and numerical results in predicting the flexural behaviour of the steering rack and pinion system.

Static Characteristics of a Rectangular Hydrostatic Thrust Bearing With a Self-Controlled Restrictor Employing a Floating Disk

1993 ◽  
Vol 115 (2) ◽  
pp. 307-311 ◽  
Author(s):  
S. Yoshimoto ◽  
Y. Anno ◽  
M. Fujimura
Keyword(s):  
Flow Rate ◽  
Applied Load ◽  
Thrust Bearing ◽  
Static Characteristics ◽  
Hydrostatic Bearing ◽  
Supply Pressure ◽  
Wide Range ◽  
Bearing Stiffness ◽  
New Type ◽  
Very High

This paper proposes a new type of a self-controlled restrictor which can achieve a very high bearing stiffness in hydrostatic bearings. This self-controlled restrictor employs a floating disk to control the mass flow rate of the oil entering the bearing clearance according to changes of the applied load. Furthermore, a hydrostatic bearing with this restrictor can theoretically achieve an infinite stiffness when the mass of a floating disk is assumed to be zero. The static characteristics of a rectangular hydrostatic thrust bearing with this self-controlled restrictor are theoretically and experimentally investigated. It was consequently shown that the proposed hydrostatic thrust bearing can achieve a very high stiffness (nearly infinite stiffness) in a very wide range of applied load independent of supply pressure.

scholarly journals Micromechanical Analyses of Debonding and Matrix Cracking in Dual-Phase Materials

2016 ◽  
Vol 83 (5) ◽  
Author(s):  
Brian Nyvang Legarth ◽  
Qingda Yang
Keyword(s):  
Biaxial Loading ◽  
Matrix Cracking ◽  
Dual Phase ◽  
Load Carrying Capacity ◽  
Matrix Cracks ◽  
Loading Direction ◽  
Load Carrying ◽  
The Matrix ◽  
Cohesive Zones ◽  
Good Agreement

Failure in elastic dual-phase materials under transverse tension is studied numerically. Cohesive zones represent failure along the interface and the augmented finite element method (A-FEM) is used for matrix cracking. Matrix cracks are formed at an angle of 55 deg−60 deg relative to the loading direction, which is in good agreement with experiments. Matrix cracks initiate at the tip of the debond, and for equi-biaxial loading cracks are formed at both tips. For elliptical reinforcement the matrix cracks initiate at the narrow end of the ellipse. The load carrying capacity is highest for ligaments in the loading direction greater than that of the transverse direction.

Theoretical Investigation of Couple Stress Squeeze Films in a Curved Circular Geometry

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Vimala Manivasakan ◽  
Govindarajan Sumathi
Keyword(s):  
Theoretical Investigation ◽  
Carrying Capacity ◽  
Couple Stress ◽  
Squeeze Flow ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Fluid Inertia ◽  
Load Carrying ◽  
Inertia Forces ◽  
Good Agreement

A theoretical investigation of the laminar squeeze flow of a couple-stress fluid between a flat circular static disk and an axisymmetric curved circular moving disk has been carried out using modified lubrication theory and microcontinuum theory. The combined effects of fluid inertia forces, curvature of the disk and non-Newtonian couple stresses on the squeeze film behavior are investigated analytically. Each of these effects and their combinations show a significant enhancement in the squeeze film behavior, and these are studied through their effects on the squeeze film pressure and the load carrying capacity of the fluid film as a function of time. Two different forms of the gapwidth between the disks have been considered, and the results have been shown to be in good agreement with the existing literature.

Load-Carrying Behaviour of Dowel-Type Timber Connections with Multiple Slotted-in Steel Plates

2011 ◽  
Vol 94-96 ◽  
pp. 43-47
Author(s):  
Xin Hai Fan ◽  
Sheng Dong Zhang ◽  
Wen Jun Qu
Keyword(s):  
Carrying Capacity ◽  
Steel Plates ◽  
Load Carrying Capacity ◽  
Timber Structures ◽  
Lateral Loads ◽  
Large Cross Section ◽  
Load Carrying ◽  
Timber Connections ◽  
Dowel Connection ◽  
Good Agreement

The multiple-shear dowel connection with slotted-in steel plates is one of the most efficient joints for large cross section timber structures. Experiments were performed on dowel-type timber connections with one, two and three slotted in steel plates under lateral loads parallel to the grain. Test variables include the number of steel plates, the spacing of the steel plates, and the dowel diameter. Results show that the load-carrying capacity of the dowel-type connection increased as the number and spacing of steel plates in the same thickness of timber specimens. Finally, a model of the load-carrying capacity of multiple shear steel-to-timber connections is presented, which showed good agreement with the results obtained in the experiment.

Numerical study of GFRP joints bearing strength reduction due to drilling-induced delamination

2019 ◽  
Vol 54 (16) ◽  
pp. 2185-2194 ◽  
Author(s):  
M Safarabadi ◽  
M Sardar
Keyword(s):  
Parametric Study ◽  
Cohesive Zone ◽  
Volume Fraction ◽  
Numerical Study ◽  
Load Carrying Capacity ◽  
Zone Method ◽  
Bearing Strength ◽  
Load Carrying ◽  
Negative Effect ◽  
Good Agreement

Delamination is one of the most common defects caused by drilling, which can have negative effect on the joint performance. This study investigates the effect of delamination on the bearing strength of [0/90]2s, [15/−75]2s, [30/−60]2s and [45/−45]2s GFRP layers numerically. Cohesive zone method and virtual crack closure technique have been used for delamination modeling and the results of these two methods have been compared. FEM results show good agreement with available experimental data. Results demonstrated that delamination reduces the bearing strength. Among four different stacking sequences, delamination has the most effect on the laminate with the stacking sequence of [0/90]2s. In both delaminated and non-delaminated models, [0/90]2s and [45/−45]2s stacking sequences have the most and the least bearing strength, respectively. By increasing the radius of delaminated zone from 3 mm to 15 mm, bearing strength does not change a lot. As the delaminated zone reaches the edge of the specimen, bearing strength reduces strongly because the layers separate completely and the load-carrying capacity reduces. A parametric study was also conducted to examine the effects of different factors. The results of parametric study showed that by increasing the volume fraction of the fiber as well as the use of carbon fiber instead of glass fiber, the bearing strength increases.

Pitting Resistance and Bending Strength of Bevel and Hypoid Gear Teeth

1992 ◽  
Author(s):  
B.-R. Höhn ◽  
H. Winter ◽  
K. Michaelis ◽  
F. Vollhüter
Keyword(s):  
Bending Strength ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Hypoid Gear ◽  
Hypoid Gears ◽  
Gear Teeth ◽  
Bevel Gears ◽  
Load Carrying ◽  
Calculation Results ◽  
Good Agreement

Abstract Bevel and hypoid gears are widely used for gears with crossed axis. The influence of a pinion offset on the load carrying capacity — pitting resistance and bending strength — is introduced in a different way in commonly used calculation methods. Load carrying and measurement investigations on the influence of pinion offset on pitting resistance and bending strength are reported. Tests show an increasing bending strength and decreasing maximum tooth root stresses with increasing pinion offset. Also a slight increase of pitting resistance and a slight decrease of the Hertzian pressure was evaluated. The load carrying calculation results for bevel gears without pinion offset, DIN 3991, is in good agreement with test results. The bending strength of hypoid gears calculated according to Niemann/Winter, is greater than that experimentally measured. For pitting resistance, however, the calculation is less than the measured results.

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