scholarly journals Discussion: “A New Numerical Technique for Computing Surface Elastic Deformation Caused by a Given Normal Pressure Distribution” (Hou, Keping, Zhu, Dong, and Wen, Shizhu, 1985, ASME J. Tribol., 107, pp. 128–131)

1985 ◽  
Vol 107 (3) ◽  
pp. 435-435 ◽  
Author(s):  
Liqun Qi ◽  
Aihua Yin
Keyword(s):  
Pressure Distribution ◽  
Elastic Deformation ◽  
Numerical Technique ◽  
Normal Pressure

A New Numerical Technique for Computing Surface Elastic Deformation Caused by a Given Normal Pressure Distribution

1985 ◽  
Vol 107 (1) ◽  
pp. 128-131 ◽  
Author(s):  
Keping Hou ◽  
Dong Zhu ◽  
Shizhu Wen
Keyword(s):  
Pressure Distribution ◽  
Elastic Deformation ◽  
Displacement Field ◽  
Numerical Technique ◽  
Surface Displacement ◽  
Normal Pressure ◽  
Normal Surface ◽  
Pressure Function ◽  
Numerical Accuracy ◽  
Iterative Calculation

This paper presents a new numerical method for computing the elastic normal surface displacement field caused by a given normal pressure distribution. The pressure function is approximated by a piecewise biquadratic polynomial on the whole domain analyzed, and the deformation of every node is expressed as a linear combination of the nodal pressures whose coefficients can be combined into a deformation matrix. Consequently, the iterative calculation of elastic deformation is simplified and the amount of work is greatly reduced. It has been proved, in addition, that the numerical accuracy of the new method is higher than that of some others.

Measurement of the Interfacial Stresses in Rolling Using the Elastic Deformation of the Roll

1987 ◽  
Vol 109 (4) ◽  
pp. 362-369 ◽  
Author(s):  
D. J. Meierhofer ◽  
K. A. Stelson
Keyword(s):  
Elastic Deformation ◽  
Normal Pressure ◽  
New Method ◽  
Frictional Stress ◽  
Stress Distributions ◽  
Strain Gages ◽  
Experimental Rolling ◽  
Mechanical Isolation ◽  
Roll Gap ◽  
Future Work

A new method to measure the frictional stresses and normal pressure in the roll gap during cold rolling, and experimental verification of this new method, are presented. The method overcomes many of the shortcomings of pin-type sensors. The elastic deformation of the roll itself is measured with strain gages, and is used to calculate the stresses between the sheet and the roll. Since no modification of the roll is necessary, the deformation process is undisturbed by the measurement. Mechanical isolation of the sensor is unnecessary. The mathematical procedure used to calculate the normal pressure and frictional stresses from the measured strains explicitly acknowledges that these strains are the result of the entire distribution of pressures and shears in the roll gap. An experimental rolling mill was constructed to verify the proposed method. Lead was rolled, and the resulting pressure and frictional stress distributions in the roll gap were measured. Several features of these distributions are in agreement with measurements made by various investigators using other techniques, thereby confirming the usefulness of the new method. Future work is proposed to increase the accuracy with which the roll gap stresses may be measured.

Effect of Thermal Distortion on Wear of Composites

1995 ◽  
Vol 117 (4) ◽  
pp. 622-628 ◽  
Author(s):  
Shingo Obara ◽  
Takahisa Kato
Keyword(s):  
Elastic Deformation ◽  
Composite Structure ◽  
Frictional Heating ◽  
Tetragonal Zirconia ◽  
Surface Profile ◽  
Normal Pressure ◽  
Oxide Ceramic ◽  
Thermal Distortion ◽  
Test Results ◽  
Worn Surface

The worn surface profile of a composite structure was experimentally and numerically investigated focusing on the effects of sliding conditions. Wear tests on composites made of an oxide ceramic and an amorphous metal against a tetragonal zirconia polycrystals-alumina were carried out under various mean contact pressures, P, and sliding velocities, V. The test results showed that the worn surface profiles of the composites changed with the PV value. A new numerical method for simulating the worn surface profile of a composite structure has been developed. The present method is based upon the assumption that the profile of a worn surface is changed by thermal distortion of the sliding bodies due to frictional heating and by elastic deformation due to normal pressure and friction traction. The calculated results were compared with the test results, and the comparison showed that the elastic deformation plays an important role in forming the worn surface profile and that the effect of thermal distortion becomes remarkable with an increase in PV values. The numerical results clarified the contribution of the thermal distortion to the change in the worn surface profile of the composite.

Some Factors Influencing Friction Brake Performance: Part 1—Investigation of Full-scale Brake Systems

1989 ◽  
Vol 111 (1) ◽  
pp. 2-7
Author(s):  
Z. Barecki ◽  
S. F. Scieszka
Keyword(s):  
Pressure Distribution ◽  
Elastic Deformation ◽  
Full Scale ◽  
Factors Influencing ◽  
Braking Torque ◽  
Brake Performance ◽  
Friction Brake ◽  
Friction Lining

In this paper the effect on braking torque of the geometry of contact between brake shoes and drums is presented. It is shown that elastic deformation as well as errors in dimensional and assembly errors substantially affect the value of the braking torque. Investigations of pressure distribution on friction lining, brake factor, brake element deformation, and wear of linings carried out on mine winder installations are presented.

Pressure Distribution Within EHD Point Contacts Based on Measured Film Thickness

Tribology ◽  
2006 ◽  
Author(s):  
Radek Poliscuk ◽  
Michal Vaverka ◽  
Martin Vrbka ◽  
Ivan Krupka ◽  
Martin Hartl
Keyword(s):  
Film Thickness ◽  
Numerical Solution ◽  
Pressure Distribution ◽  
Elastic Deformation ◽  
Contact Fatigue ◽  
Lubricant Film ◽  
Rolling Contact ◽  
Lubricant Film Thickness ◽  
Machine Elements ◽  
Lubricated Contact

Surface topography significantly influences the behavior of lubricated contacts between highly loaded machine elements. Most oil- or grease- lubricated machine elements such as gears, rolling bearings, cams and traction drives operate in mixed lubrication conditions and the lubricant film thickness is directly related to the main practical performance parameters such as function, wear, contact fatigue and scuffing. For determination wear and especially contact fatigue, the values and distribution of the pressure in rolling contact are required. The theoretical studies usually involve the numerical solution of pressure and film thickness in the contact, using some physical mathematical model built around the Reynolds equation to describe the flow and the theory of elastic deformation of semi-infinite bodies. Such calculations can be extremely time consuming, especially when lubricant films are very thin and/or contact load very high. This study is aimed at obtaining pressure distribution within lubricated contact from measured film thickness. Lubricant film thickness distribution within the whole concentrated contact is evaluated from chromatic interferograms by thin film colorimetric interferometry. Consequently, an elastic deformation is separated from the film thickness, geometry and mutual approach of the surfaces. Calculation of the pressure distribution is based on inverse elasticity theory. EHD lubricated contact with smooth surfaces of solids was first investigated. Calculated pressure, distributions were compared with data obtained from full numerical solution to check the accuracy. The approach was also applied to surfaces with dents and their influence on distribution of pressure in lubricant film.

Rolling Contact With Friction and Non-Hertzian Pressure Distribution

1989 ◽  
Vol 56 (4) ◽  
pp. 814-820 ◽  
Author(s):  
C. Liu ◽  
B. Paul
Keyword(s):  
Pressure Distribution ◽  
Numerical Technique ◽  
Contact Region ◽  
Three Dimensional ◽  
Contact Problems ◽  
Rolling Contact ◽  
Sliding Contact ◽  
Hertzian Contact ◽  
Limiting Case ◽  
Large Spin

A numerical technique has been developed to deal with three-dimensional rolling contact problems with an arbitrary contact region under an arbitrary pressure. Results of this technique are checked against existing solutions for cases of Hertzian contact. A solution for a case of non-Hertzian contact is also presented. This numerical technique works satisfactorily for cases with small spin creepage. For cases of large spin creepage, we utilize a recent work (by the authors) for the limiting case of fully developed sliding contact.

Hydroelastic Behavior of Air-Supported Flexible Floating Structures

2002 ◽  
Author(s):  
Tomoki Ikoma ◽  
Koichi Masuda ◽  
Hisaaki Maeda ◽  
Chang-Kyu Rheem
Keyword(s):  
Pressure Distribution ◽  
Energy Absorption ◽  
Elastic Deformation ◽  
Wave Energy ◽  
Distribution Method ◽  
Elastic Deformations ◽  
Floating Structures ◽  
Air Chamber ◽  
Air Cushion ◽  
Offshore Field

A pontoon type very large floating structure has elastic deformations in ocean waves. The deformation is larger than that of a semi-submergible type one. Thus, a pontoon type one will be installed to tranquil shallow water field enclosed by breakwaters. Moreover, a semi-submergible one will be applicable to development at offshore field. The authors has developed a pontoon type VLFS with an OWC (oscillating water column) type wave energy absorption system. This can be install to offshore field being deep water relatively. Such VLFS can reduce not only the elastic deformation but also the wave drifting forces. However, it is very difficult to reduce the wave drifting forces effectively because an effect of the reduction depends on the wave energy absorption. Therefore, the authors propose an air supported type VLFS. This idea has been already proposed. However, it wasn’t handled a flexible structure. Such an air-supported structure makes to transmit many waves. Therefore, the wave drifting forces may not increase. In addition, the elastic deformation may decrease because pressure distribution due to the incident waves becomes constant at the bottom of the structure, i.e. the pressure is constant in a same air chamber. We develop the program code for the analysis of the hydrodynamic forces on the VLFS with the air cushion. The potential flow theory is applied and the pressure distribution method is used to the analysis of the wave pressures. The zero-draft is assumed in this method. The pressure and volume change of the air cushion are linearized. In this paper, basic characteristics of the elastic deformations of the air-supported flexible floating structures are investigated. We confirm the effectiveness, and discuss behaviors of the water waves in air chamber areas.

Influence of Surface Waviness and Roughness on the Normal Pressure Distribution in the Hertzian Contact

1987 ◽  
Vol 109 (3) ◽  
pp. 462-469 ◽  
Author(s):  
J. Seabra ◽  
D. Berthe
Keyword(s):  
Surface Roughness ◽  
Contact Problem ◽  
Pressure Distribution ◽  
Variational Formulation ◽  
Virtual Work ◽  
Normal Pressure ◽  
Hertzian Contact ◽  
Surface Waviness ◽  
Normal Contact ◽  
Surface Imperfections

Contact stresses are one of the most important parameters in the analysis of a contact problem found for instance, in the design of gears and roller bearings. In this work the influence of geometrical surface imperfections on the normal pressure distribution in the contact is studied. A variational formulation based on the principle of complementary virtual work is used to solve the normal contact problem. The normal contact between two elastic half-spaces is considered, as the contact surface is small when compared to the dimensions of the contacting bodies. Results are presented to determine the influence of surface roughness, wavelength, and amplitude on the normal pressure distribution.

scholarly journals SIMULATION OF A SINGLE THIRD-BODY PARTICLE IN FRICTIONAL CONTACT

2020 ◽  
pp. 537
Author(s):  
Qiang Li
Keyword(s):  
Boundary Element Method ◽  
Stress Distribution ◽  
Pressure Distribution ◽  
Tangential Stress ◽  
Frictional Contact ◽  
Normal Pressure ◽  
Contact Interface ◽  
Third Body ◽  
Rigid Particles ◽  
Force Moment

Contact of a single third-body particle between two plates is simulated using the Boundary Element Method. The particle is considered as deformable, and the Coulomb’s law of friction is assumed at the contact interface. The normal pressure distribution and tangential stress distribution in contact as well as the macroscopic force and force moment are calculated. Several movement modes are shown to be possible: rolling, rotation, or sticking during the loading. It is found that, differing from rigid particles, the state of particle may change during the loading. The particle may stick to the plates initially, but rotation may occur when the load becomes larger. Examples with the same and different coefficients of friction are presented to show kinematics of particle. The method can be further applied to simulation of multiple third-body particles.

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.

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