Discussion: “A Numerical Solution of the Elastohydrodynamic Film Thickness in an Elliptical Contact” (Cheng, H. S., 1970, ASME J. Lubr. Technol., 92, pp. 155–161)

1970 ◽  
Vol 92 (1) ◽  
pp. 161-162
Author(s):  
Harold E. Sliney
Keyword(s):  
Film Thickness ◽  
Numerical Solution ◽  
Elliptical Contact ◽  
Elastohydrodynamic Film Thickness

A Numerical Solution of the Elastohydrodynamic Film Thickness in an Elliptical Contact

1970 ◽  
Vol 92 (1) ◽  
pp. 155-161 ◽  
Author(s):  
H. S. Cheng
Keyword(s):  
Film Thickness ◽  
Numerical Solution ◽  
Reynolds Equation ◽  
Contact Theory ◽  
Line Contact ◽  
Hertz Theory ◽  
Inlet Region ◽  
Elliptical Contact ◽  
Elastohydrodynamic Film Thickness ◽  
Circular Contact

A numerical solution of the elastohydrodynamic film thickness in an elliptical contact is developed. The two-dimensional Reynolds’ equation in the inlet region is solved by a finite-difference method. The deformation contour in the inlet region is calculated according to the classical Hertz theory for elliptical contacts. Results are presented as side leakage film reduction factors, which are defined as the ratios of the film thickness of the finite contact to that calculated by a line contact theory based on the same maximum Hertz stress. The results obtained for a b/a → ∞, which corresponds to a line contact, and for b/a = 1, which corresponds to a circular contact, agree with those obtained in [2]. Comparison with experimental data [1] indicates that this theory predicts a film thickness slightly higher than those measured by the experiment.

Optimized Mapping of Pressure in Lubricated Point Contacts Based on Measured Film Thickness

2007 ◽  
Author(s):  
Radek Polisˇcˇuk ◽  
Michal Vaverka ◽  
Martin Vrbka ◽  
Ivan Krˇupka ◽  
Martin Hartl
Keyword(s):  
Film Thickness ◽  
Numerical Solution ◽  
Point Contact ◽  
Contact Fatigue ◽  
Lubricant Film ◽  
Rolling Contact ◽  
Experimental Film ◽  
Lubricated Contacts ◽  
Practical Performance ◽  
Traction Drives

The surface topography plays significant role in lifetime of highly loaded machine parts with lubricated contacts. Many elements like gears, rolling bearings, cams and traction drives operate in mixed lubrication conditions, where the lubricant film behavior closely implies the main practical performance parameters such as friction wear, contact fatigue and scuffing. For prediction of wear and especially contact fatigue, the values and distribution of the pressure in rolling contact are often required. The usual theoretical approach based on numerical solution of physical-mathematical models built around the Reynolds equation can be extremely time consuming, especially when lubricant films are very thin, and contact load and required resolution very high. This study presents a further refined approach to our previously published experimental method, based on on inverse elasticity theory and fast convolution transformation between the lubricant film thickness map and the pressure distribution within the point contact. The experimental film thickness maps of EHD lubricated contacts with smooth and dented surfaces were processed using colorimetric interferometry and validated using numerical solution, in order to calibrate numerical parameters and to find limits of the new approach.

Numerical Solution of the Planar Hydrostatic Foil Bearing

1979 ◽  
Vol 101 (1) ◽  
pp. 86-91 ◽  
Author(s):  
A. Eshel
Keyword(s):  
Steady State ◽  
Film Thickness ◽  
Computer Program ◽  
Numerical Solution ◽  
Asymptotic Approach ◽  
State Problem ◽  
Shooting Technique ◽  
Foil Bearing ◽  
Approach To Steady State ◽  
Steady State Problem

The steady state problem of the planar hydrostatic foil bearing is analyzed and solved numerically. Two techniques of solution are used. One method is simulation in time with asymptotic approach to steady state. This is achieved by a preprocessor which automatically sets up the numerical computer program. The second method is an iterative shooting technique. The results agree well with one another. Curves of pressure and typical film thickness versus flow are presented.

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