A Hybrid Film Thickness Evaluation Scheme Based on Multi-Channel Interferometry and Contact Mechanics

1999 ◽  
Vol 122 (1) ◽  
pp. 16-22 ◽  
Author(s):  
J. Lord ◽  
A. Jolkin ◽  
R. Larsson ◽  
O. Marklund
Keyword(s):  
Refractive Index ◽  
Film Thickness ◽  
Contact Region ◽  
Thickness Measurement ◽  
Interesting Phenomenon ◽  
Thickness Profile ◽  
Thickness Determination ◽  
Evaluation Scheme ◽  
Initial Film ◽  
Correction Scheme

A hybrid evaluation scheme for EHL film thickness determination is proposed and discussed. The film thickness profile in the contact region is measured using interferograms produced with a novel multi channel interferometry method. Since the refractive index distribution in the contact is pressure-dependent, and the initial film thickness profile will be evaluated assuming atmospheric pressure, a refractive index correction scheme is employed. The correction scheme is based on the Lorenz-Lorentz equation and a pressure-density relation together with a numerical pressure solver taking the initial film thickness measurement as input. The film thickness determination scheme is applied to an interesting phenomenon that can be observed at sliding conditions when the discrepancy occurred in the form of a deep and large dimple in the conjunction. Such a dimple appeared instead of the conventional plateau. The phenomenon was studied under different degrees of sliding. The detailed film thickness maps and pressure distributions for highly loaded EHL conjunctions at high degrees of sliding are produced using a hybrid evaluation scheme. The results are analyzed and discussed. [S0742-4787(00)00301-5]

scholarly journals The Effects of Artificially-Produced Defects on the Film Thickness Distribution in Sliding EHD Point Contacts

1982 ◽  
Vol 104 (3) ◽  
pp. 365-375 ◽  
Author(s):  
C. Cusano ◽  
L. D. Wedeven
Keyword(s):  
Film Thickness ◽  
Contact Region ◽  
Thickness Distribution ◽  
Point Contact ◽  
Optical Interferometry ◽  
Point Contacts ◽  
Thickness Profile ◽  
Inlet Region

The effects of artificially-produced dents and grooves on the elastohydrodynamic (EHD) film thickness profile in a sliding point contact are investigated by means of optical interferometry. The defects, formed on the surface of a highly polished ball, are held stationary at various locations within and in the vicinity of the contact region while the disk is rotating. It is shown that the defects, having a geometry similar to what can be expected in practice, can dramatically change the film thickness which exists when no defects are present in or near the contact. This change in film thickness is mainly a function of the position of the defects in the inlet region, the geometry of the defects, the orientation of the defects in the case of grooves, and the depth of the defect relative to the central film thickness.

Influence of Seawater Refractive Index on the Precision of Oil Film Thickness Measurement by Differential Laser Triangulation

2015 ◽  
Vol 42 (4) ◽  
pp. 0408004
Author(s):  
耿云飞 Geng Yunfei ◽  
陈曦 Chen Xi ◽  
金文 Jin Wen ◽  
张惠群 Zhang Huiqun ◽  
邬海强 Wu Haiqiang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Film Thickness ◽  
Thickness Measurement ◽  
Laser Triangulation ◽  
Oil Film ◽  
Film Thickness Measurement

Optical Interferometric Observations of the Effects of a Bump on Point Contact EHL

1992 ◽  
Vol 114 (4) ◽  
pp. 779-784 ◽  
Author(s):  
M. Kaneta ◽  
T. Sakai ◽  
H. Nishikawa
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Numerical Simulations ◽  
Contact Region ◽  
Thickness Distribution ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Interesting Phenomenon ◽  
Contact Conditions ◽  
Average Speed

The effects of surface kinematic conditions on micro-elastohydrodynamic lubrication (micro-EHL) are investigated under rolling and/or sliding point contact conditions using the optical interferometry technique. A long bump of chromium sputtered on the surface of a highly polished ball is used as a model asperity. It is shown that the film thickness distribution or the elastic deformation of the bump is influenced significantly by the surface kinematic conditions and the orientation of the bump. An interesting phenomenon is also found when contacting surfaces move with different speeds; the thin film formed on a transversely oriented bump existing at the entrance of the contact travels through the contact region at the average speed of the surfaces. The experimental results obtained qualitatively confirm published numerical simulations.

RESOLUTION IN PIXE THIN FILM THICKNESS DETERMINATION

1991 ◽  
Vol 01 (03) ◽  
pp. 259-270 ◽  
Author(s):  
J. MIRANDA ◽  
A. OLIVER ◽  
F.J. RUIZ ◽  
J.M. SANTANA
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Thickness Measurement ◽  
Copper Films ◽  
Thin Film Thickness ◽  
Thickness Determination ◽  
Beam Incident ◽  
Sputtering Yields ◽  
Film Thickness Measurement ◽  
Titanium Substrates

The resolution of several methods for thin film thickness measurement using PIXE, based on the variation of the proton beam incident energy, is discussed. In order to evaluate the resolution, sputtering of copper films, deposited on aluminum and titanium substrates by argon ions is used. Sputtering yields are obtained through thickness changes, and then compared to other experimental and theoretical values. Good agreement is found, thus confirming the accuracy of PIXE as a method for film thickness determination.

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