Elastohydrodynamic Lubrication Between Rolling and Sliding Ceramic Cylinders: An Experimental Investigation1

2000 ◽  
Vol 122 (4) ◽  
pp. 721-724 ◽  
Author(s):  
T. Sperrfechter ◽  
R. Haller
Keyword(s):  
Thermal Conductivity ◽  
Film Thickness ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Elastohydrodynamic Lubrication ◽  
Ceramic Materials ◽  
Oil Film ◽  
Thin Film Sensors ◽  
Line Contacts ◽  
Clear Increase

The present work focuses on the investigation of the influence of bulk ceramic materials on the behavior of elastohydrodynamically (EHD) lubricated line contacts. The materials alumina Al2O3, zirconium oxide ZrO2 and aluminum nitride (AIN) are used. Comparative measurements were taken with steel disks made of 42CrMo4. Of primary importance are the material parameters Young’s modulus and thermal conductivity. The experimental variables pressure, temperature and oil film thickness in the EHD contact of a two disk test rig were measured with the aid of evaporated thin film sensors. As the results show, an increase in the Young’s modulus causes a clear increase of the pressure level. The oil film thickness distributions show a decline of the flattening width and of the constriction occurring at the contact outlet. The influence of the material with respect to its thermal conductivity dominates, above all, in the region of the load transmitting contact zone. The transition from a good to a bad conductor of heat causes a rise in temperature, more prominent for materials with lower thermal conductivities. This leads to viscosity decrease causing clearly reduced oil film thicknesses in the contact. [S0742-4787(00)01404-1]

Influence of Different Viscosity Lubricant to Finite Line Contacts on Elastohydrodynamic Lubrication (EHL) under Oscillating

2012 ◽  
Vol 538-541 ◽  
pp. 1939-1944
Author(s):  
Yan Fei Wang ◽  
Tong Shu Hua ◽  
Hao Yang Sun
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Oil Film ◽  
Entrainment Velocity ◽  
Finite Line Contact ◽  
Line Contacts ◽  
Finite Line ◽  
Contact Roller ◽  
Two Parameters ◽  
Experimental Rig

To make further researches into the elastohydrodynamic lubrication properties of a finite line contact roller, oscillating experiments were carried out on made overload experimental rig for oil film measurement using optical interference technique. Film thickness and shape were measured in two kinds of viscosity polyisobutylene. This study indicates that both lubricant viscosity and roller entrainment velocity play an important role on EHL of finite line contacts. On motion, the more increase in viscosity or speed, the thicker the oil film thickness, simultaneity edge effect is distinctly intensified and film thickness increases less on roller end, difference of the film thickness is increased between roller end and the central. Above two parameters are significant for logarithmic profile roller in crowning design.

Influence of Surface Waviness on the Thermal Elastohydrodynamic Lubrication of an Eccentric-Tappet Pair

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
J. Wang ◽  
C. H. Venner ◽  
A. A. Lubrecht
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Surface Waviness ◽  
Film Pressure ◽  
Oil Film ◽  
Working Cycle ◽  
Temperature Oscillations ◽  
Minimum Film Thickness ◽  
Traction Coefficient ◽  
Oil Film Pressure

The effect of single-sided and double-sided harmonic surface waviness on the film thickness, pressure, and temperature oscillations in an elastohydrodynamically lubricated eccentric-tappet pair has been investigated in relation to the eccentricity and the waviness wavelength. The results show that, during one working cycle, the waviness causes significant fluctuations of the oil film, pressure, and temperature, as well as a reduction in minimum film thickness. Smaller wavelength causes more dramatic variations in oil film. The fluctuations of the pressure, film thickness, temperature, and traction coefficient caused by double-sided waviness are nearly the same compared with the single-sided waviness, but the variations are less intense.

Theoretical and experimental studies of the oil film in lubricated point contact

1966 ◽  
Vol 291 (1427) ◽  
pp. 520-536 ◽  
Keyword(s):  
Surface Layer ◽  
Film Thickness ◽  
Strong Evidence ◽  
Experimental Studies ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Experimental Results ◽  
Point Contacts ◽  
Previous Theory ◽  
Oil Film

A technique using Newton’s rings for mapping the oil film of lubricated point contacts is described. A theoretical value for the film thickness of such contacts in elastohydrodynamic lubrication is derived. The experimental results give the exit constriction predicted by previous theory but never shown in detail. The comparison of theoretical and experimental oil film thicknesses, which is satisfactorily accurate, gives strong evidence for a viscous surface layer some 1000Å thick. This film agrees with the known ‘lubricating power’ of the various oils tested.

Size effect on thermal elastohydrodynamic lubrication of industrial chain bush-pin hinge pair

2019 ◽  
Vol 71 (9) ◽  
pp. 1080-1085 ◽  
Author(s):  
Mingyu Zhang ◽  
Jing Wang ◽  
Yi Liu ◽  
Longjie Dai ◽  
Zhaohua Shang
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Temperature Rise ◽  
Elastohydrodynamic Lubrication ◽  
Curvature Radius ◽  
Line Contact ◽  
Content Type ◽  
Oil Film ◽  
Industrial Chain ◽  
Infinite Line

Purpose The purpose of this paper is to use elastohydrodynamic lubrication (EHL) theory to study the variation of the equivalent curvature radius “R” on the change of oil film thickness, pressure, temperature rise and friction coefficient in the contact zone between bush-pin in industrial chain drive. Design/methodology/approach In this paper, the contact between bush and pin is simplified as infinitely long line contact. The lubrication state is studied by numerical simulation using steady-state line contact thermal EHL. The two constitutive equations, namely, Newton fluid and Ree–Eyring fluid are used in the calculations. Findings It is found that with the increase of equivalent curvature radius, the thickness of oil film decreases and the temperature rise increases. Under the same condition, the friction coefficient of Newton fluid is higher than that of Ree–Eyring fluid. When the load increases, the oil film thickness decreases, the temperature rise increases and the friction coefficient decreases; and the film thickness increases with the increase of the entraining speed under the condition “R < 1,000 mm”. Research limitations/implications The infinite line contact assumption is only an approximation. For example, the distances between the two inner plates are 5.72 mm, by considering the two parts assembled into the inner plates, the total length of the bush is less than 6 mm. The diameter of the pin and the bore diameter of the bush are 3.28 and 3.33 mm. However, the infinite line contact is also helpful in understanding the general variation of oil film characteristics and provides a reference for the future study of finite line contact of chain problems. Originality/value The change of the equivalent radius R on the variation of the oil film in the contact of the bush and the pin in industrial chain drive was investigated. The size effect influences the lubrication characteristic greatly in the bush-pin pair.

scholarly journals Neutron Multiple Number as a Factor Ruling Both the Abundance and Some Material Properties of Elements

2017 ◽  
Vol 6 (3) ◽  
pp. 37
Author(s):  
Yoshiharu Mae
Keyword(s):  
Thermal Conductivity ◽  
Young’S Modulus ◽  
Melting Temperature ◽  
Material Properties ◽  
Young's Modulus ◽  
Materials Properties ◽  
Unique Pattern ◽  
The Universe

The abundance of elements in the universe was plotted on the TC-YM diagram. The most abundant elements show the unique pattern drawing a quadrant. Next, the neutron multiple number, the number of neutron per proton in the nucleus, was introduced. The neutron multiple numbers of elements show the same pattern as the abundance of elements on the diagram. As a result, the abundance of elements shows a good correlation with neutron multiple numbers of elements. With increasing neutron multiple number, the abundance decreases. Besides, the neutron multiple number relates to the materials properties such as the Young’s modulus, thermal conductivity and melting temperature of elements.

Electrophoretic Deposition of Single Wall Carbon Nanotube Films and Characterization

2014 ◽  
Vol 1752 ◽  
pp. 59-63
Author(s):  
Junyoung Lim ◽  
Maryam Jalali ◽  
Stephen A. Campbell
Keyword(s):  
Carbon Nanotube ◽  
Film Thickness ◽  
Young’S Modulus ◽  
Electrophoretic Deposition ◽  
Flexible Electronics ◽  
Rutherford Backscattering Spectrometry ◽  
Young's Modulus ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
Nanotube Films

ABSTRACTElectrophoretic deposition enables the rapid deposition of single wall carbon nanotube films at room temperature. An accurate, reproducible film thickness can be obtained by controlling electric field strength, suspension concentration, and time. To investigate the electrical and mechanical properties of such films, we recorded electric resistance and Young’s modulus using I-V characterization and a nanoindenter, respectively. The measured resistivity of the films varied from 2.14 × 10-3 to 7.66 × 10-3 Ω·cm, and the Young’s modulus was 4.72 to 5.67 GPa, independent of film thickness from 77 to 134 nm. These results indicated that the mechanical and electrical properties of film are comparable with previously reported methods such as layer by layer deposition even though we achieved much higher deposition rates. We also measured the film mass density which is usually unrecorded even though it is an important parameter for MEMS/NEMS device actuation. The film density was found with conventional thickness measurement and Rutherford backscattering spectrometry. It varied from 0.12 to 0.54 g/cm3 as the film thickness increased. This method could be extended to applications of CNT films for flexible electronics or high frequency RF MEMS devices.

Thermal Non-Newtonian Elastohydrodynamic Lubrication of Line Contacts Under Simple Sliding Conditions

1992 ◽  
Vol 114 (2) ◽  
pp. 317-327 ◽  
Author(s):  
Shao Wang ◽  
T. F. Conry ◽  
C. Cusano
Keyword(s):  
Film Thickness ◽  
Surface Temperature ◽  
Thermal Effects ◽  
Elastohydrodynamic Lubrication ◽  
Reduction Factor ◽  
Simple Formulation ◽  
Maximum Surface ◽  
Line Contacts ◽  
Traction Coefficient ◽  
Maximum Surface Temperature

A computationally simple formulation for the stationary surface temperature is developed to examine the thermal non-Newtonian EHD problem for line contacts under simple sliding conditions. Numerical results obtained are used to develop a formula for a thermal and non-Newtonian (Ree-Eyring) film thickness reduction factor. Results for the maximum surface temperature and traction coefficient are also presented. The thermal effects on film thickness and traction are found to be more pronounced for simple sliding than for combined sliding and rolling conditions.

Effect of Thermal Properties of a Coated Elastohydrodynamic Lubrication Line Contact Under Various Slide-to-Roll Ratios

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Huaiju Liu ◽  
Caichao Zhu ◽  
Zonglin Gu ◽  
Zhanjiang Wang ◽  
Jinyuan Tang
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Elastohydrodynamic Lubrication ◽  
Temperature Fields ◽  
Line Contact ◽  
Oil Film ◽  
Line Contacts ◽  
Energy Equations ◽  
Thermal Conductivities

A numerical thermal elastohydrodynamic lubrication (EHL) model is developed for coated line contacts by considering both the mechanical properties and the thermal properties of the coating and the substrate. The temperature fields within the oil film and within the solids are solved by deriving the energy equations for the solids and the oil film. Heat continuity conditions are satisfied at the interfaces between the solids and the oil film, and the coating/substrate interfaces. Effects of the slide-to-roll ratio (SR), the thermal conductivities of the coating bodies, and the oil film on temperature fields are studied.

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