Externally Pressurized Step Journal Bearings

1961 ◽  
Vol 83 (4) ◽  
pp. 595-602 ◽  
Author(s):  
Clarence R. Adams ◽  
Juraj Dworski ◽  
Edward M. Shoemaker
Keyword(s):  
Theoretical Method ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Test Procedures ◽  
Paper Test ◽  
Static And Dynamic Stability ◽  
Load Carrying ◽  
Rotating Shafts ◽  
Design Simplicity ◽  
Gas Journal Bearing

An externally pressurized gas journal bearing which achieves its load carrying capability by utilizing flow throttling dams parallel to the direction of rotation is discussed in this paper. Test procedures and equipment used to develop this bearing concept are described. A theoretical method of determining pressure distribution and load carrying capacity for the bearing is presented and correlated with experimental data for non-rotating shafts. Experiments showing the behavior of the bearing under shaft whirl conditions are described and illustrated. Suggested ranges of the design parameters are indicated. The paper also points out advantages accruing from the design simplicity as well as the static and dynamic stability of this bearing concept.

Theoretical Analysis of Externally Pressurized Air Journal Bearing

1970 ◽  
Vol 12 (2) ◽  
pp. 123-129 ◽  
Author(s):  
B. C. Majumdar
Keyword(s):  
Experimental Data ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Dimensional Parameters ◽  
Bearing Design

A theoretical investigation is made to predict the performance of an externally pressurized air journal bearing having several pressure sources. The pressure distribution, which leads to the determination of load-carrying capacity and flow requirement, is obtained by solving Reynolds equation numerically. The load and flow, expressed in non-dimensional parameters, are presented for different bearing design parameters (dimensionless). The results predicted by this method are compared with others' experimental data.

scholarly journals Dynamic Carrying Capacity Analysis of Double-Row Four-Point Contact Ball Slewing Bearing

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yunfeng Li ◽  
Di Jiang
Keyword(s):  
Dynamic Load ◽  
Carrying Capacity ◽  
Point Contact ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Double Row ◽  
Slewing Bearing ◽  
Load Carrying ◽  
Bearing Design ◽  
Capacity Surface

Carrying capacity is the most important performance index for slewing bearings. Maximizing the carrying capacity of slewing bearing is one pursuing goal for the bearing designer; this is usually realized by optimizing the design parameters. A method of analyzing the carrying capacity of double-row four-point contact ball slewing bearing by using dynamic carrying capacity surfaces was proposed in this paper. Based on the dynamic load carrying capacity surface of the slewing bearing, the effect of changes of the bearing design parameters, such as axial clearance, raceway groove radius coefficient, and contact angle, on the dynamic carrying capacity of the slewing bearing was researched; the trend and the degree of the effect of the micro changes of the bearing design parameters on the dynamic load carrying capacity of the bearing were discussed, and the results provide the basis for optimizing the design parameter of this type of slewing bearing.

scholarly journals Design and Parameter Study of a Self-Compensating Hydrostatic Rotary Bearing

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Xiaobo Zuo ◽  
Shengyi Li ◽  
Ziqiang Yin ◽  
Jianmin Wang
Keyword(s):  
Influence Factors ◽  
Resistance Ratio ◽  
Design Parameters ◽  
Parameter Study ◽  
Load Carrying Capacity ◽  
Clearance Ratio ◽  
Load Carrying ◽  
Static Performance ◽  
Initial Clearance ◽  
Flow Conservation

The influence of design parameters on the static performance of a newly designed self-compensating hydrostatic rotary bearing was investigated. The bearing was designed by incorporating the main attributes of angled-surface self-compensating bearing and opposed-pad self-compensating bearing. A governing model based on flow conservation was built to theoretically study the static performance, and the methodology was validated by experiments. It is pointed out that the influence factors on the bearing static performance are the designed resistance ratio of the restricting land to the bearing land, the inner resistance ratio of the land between pockets to that between the pocket and the drain groove, the initial clearance ratio of the restricting gap to the bearing gap, and the semiconical angle. Their effects on the load carrying capacity and stiffness were investigated by simulation. Results show that the optimum designed resistance ratio is 1; the initial clearance ratio should be small, and the inner resistance ratio should be large.

The Hydrostatic Gas Journal Bearing With Journal Rotation and Vibration

1964 ◽  
Vol 86 (2) ◽  
pp. 328-336 ◽  
Author(s):  
J. W. Lund
Keyword(s):  
Carrying Capacity ◽  
Journal Bearing ◽  
Load Carrying Capacity ◽  
Restricted Feeding ◽  
Eccentricity Ratio ◽  
Small Vibration ◽  
Small Eccentricity ◽  
First Order ◽  
Load Carrying ◽  
Gas Journal Bearing

This paper analyzes the load-carrying capacity of the externally pressurized gas journal bearing, including the effect of journal rotation and vibration. The analysis assumes small eccentricity ratio and small vibration amplitude such that a first-order perturbation solution is obtained. The gas is fed to the bearing through orifice-restricted feeding holes around the circumference in one or two feeding planes. The number of feeding holes is sufficiently large to permit treating the feeding planes as line sources. Results are given for the load-carrying capacity and the attitude angle.

scholarly journals Analytical Assessment and Comparison of Wood Strength and Density Effect in the Design of Three Connection Types in Double-Shear

2021 ◽  
Author(s):  
Elza M. M. Fonseca ◽  
Pedro A. S. Leite ◽  
Lino D. S. Silva ◽  
Vânia S. B. Silva ◽  
Hernâni M. Lopes
Keyword(s):  
Tensile Load ◽  
Shear Plane ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Lower Strength ◽  
Double Shear ◽  
Load Carrying ◽  
Strength Material ◽  
Analytical Assessment ◽  
Wood Strength

This work presents the results of three connection types in double-shear with dowel fasteners, using the simplified equations from the Eurocode 5. All design parameters were established and compared using three different wood strength and density properties, which constitute the members connections. Eighty-one connections were obtained, allowing to conclude about the number of fasteners needed to the applied tensile load. An increase in the number of dowels was obtained with the increased applied tensile load, lower dowel diameter, lower wood density, and lower strength material in all connection types in the study. The design characteristic load-carrying capacity per shear plane and fastener also decrease with the previously considered parameters.

Field Evaluation of Steel Girder Bridge

1997 ◽  
Vol 1594 (1) ◽  
pp. 140-146 ◽  
Author(s):  
Vijay K. Saraf ◽  
Andrzej S. Nowak
Keyword(s):  
Carrying Capacity ◽  
Field Evaluation ◽  
Load Test ◽  
Load Carrying Capacity ◽  
Test Procedures ◽  
Steel Girder ◽  
Weigh In Motion ◽  
Load Carrying ◽  
Steel Girder Bridge ◽  
Girder Bridge

The objective of the study was to verify the load-carrying capacity of an existing steel girder bridge. The selected structure was a 70-year-old deteriorated bridge in Michigan. The load-carrying capacity of the bridge was in question because of extensive corrosion of the steel girders. An initial rating indicated that the bridge had a marginal operating rating factor for 11-axle two-unit trucks, which are the heaviest vehicles allowed in Michigan. To avoid the load limit posting, it was decided that investigators would verify by nondestructive testing whether the bridge is safe to carry normal truck traffic. The test procedures used on the selected bridge included tests for obtaining stress histogram measurements and weigh-in-motion measurements and a proof load test. The methodology and the results are described.

Parametric study of truss bridges by the post-tensioning method

2005 ◽  
Vol 32 (2) ◽  
pp. 420-429 ◽  
Author(s):  
Kyoung-Bong Han ◽  
Sun-Kyu Park
Keyword(s):  
Carrying Capacity ◽  
Steel Structures ◽  
High Strength ◽  
Elastic Behavior ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Prestressing Force ◽  
Load Carrying ◽  
Post Tensioning ◽  
Post Tensioned

The post-tensioning method has been successfully used to improve the performance of existing concrete structures. Applications of the method are rare in steel structures, however. Post-tensioning using high-strength cables or bars can be effectively used to increase the working load carrying capacity of steel structures. In this paper, the elastic behavior of post-tensioned trusses with straight and draped tendon profiles for truss strengthening is examined. The effects of design parameters such as the tendon profile, truss type, prestressing force, and tendon eccentricity on working load and deflection of trusses are studied. The results show that the allowable load of a truss increases proportionally with the increase in prestressing force and eccentricity. Post-tensioning enlarges the elastic range, increases the redundancy, and reduces the deflection and member stresses, eventually increasing the load-carrying capacity of truss bridges.Key words: post-tensioning method, steel structures, post-tensioned trusses, truss strengthening, design parameters, load-carrying capacity.

A Novel Design of a Self-Sensing Compensating Restrictor/Pad Module for Hydrostatic Bearings

2014 ◽  
Author(s):  
Cho-Yun Yang ◽  
Cho-Yu Yang ◽  
Jia-Wei Lu ◽  
Wei-Chih Lee ◽  
Yu-Min Hung ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Pressure Ratio ◽  
Lumped Parameter Model ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Hydrostatic Bearings ◽  
Lumped Parameter ◽  
Load Carrying ◽  
Membrane Type ◽  
The Relationship

This paper proposes the design of a self-sensing compensating restrictor/pad module for hydrostatic bearings. The module consists of a bearing pad and the associated restrictor featuring the characteristics of self-sensing compensation and easy installation. The paper first introduces the configuration of the proposed module. Then, the lumped parameter model was used to derive the equation for the relationship between the pocket pressure and the bearing gap. Furthermore, equations governing the stiffness and load-carrying capacity of the bearing were also obtained. Influences of the design parameters, such as the land length and pressure ratio, on bearing performance and the feasibility of the new design were studied both analytically and experimentally. Results of the theoretical analysis were compared with that of the experiment. Superior performances on the aspects of stiffness and load-carrying capacity, as well as time delay due to the distance between restrictor and bearing pad to the traditional restrictors such as capillary and orifice were achieved. In addition, the proposed restrictor possesses the advantages of simplicity for both manufacturing and assembly in comparison with the membrane-type restrictors.

Influence of Yield Strength Variability over Cross-Section to Steel Beam Load-Carrying Capacity

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala
Keyword(s):  
Yield Strength ◽  
Cross Section ◽  
Carrying Capacity ◽  
Bending Moment ◽  
Statistical Characteristics ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Strength Variability ◽  
Hot Rolled ◽  
Hot Rolled Steel

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.

Fuzzy Sets Theory in Comparison with Stochastic Methods to Analyse Nonlinear Behaviour of a Steel Member under Compression

2005 ◽  
Vol 10 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Z. Kala
Keyword(s):  
Fuzzy Sets ◽  
Carrying Capacity ◽  
Stochastic Methods ◽  
Nonlinear Behaviour ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Input Parameters ◽  
Stochastic Solution ◽  
Fuzzy Solution ◽  
Sets Theory

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.

Sign in / Sign up

Export Citation Format

Share Document