Laser-induced fluorescence for film thickness mapping in pure sliding lubricated, compliant, contacts
File(s)Tribology International_43_11_2010.pdf (1.21 MB)
Accepted version
Author(s)
Myant, C
Reddyhoff, T
Spikes, HA
Type
Journal Article
Abstract
A laser-induced fluorescence (LIF) technique has been used to measure fluid film thickness in a compliant, sliding contact under low-load/low-pressure conditions. The soft contact between an elastomer hemisphere and a glass disc is lubricated by a liquid containing fluorescent dye. The contact is then illuminated with 532 nm laser light through the glass disc, and viewed with a fluorescence microscope. From the intensity of emitted radiation, film thickness maps of the contact are determined. Previous calibration procedures have used a separate calibration piece and test specimen with possible errors due to differences in reflectivity between the calibration and test specimens. In the work reported in this paper a new calibration process is employed using the actual test sample, thereby avoiding such errors. Results are reported for a sliding contact between PDMS and glass, lubricated with glycerol and water solutions under fully flooded and starved conditions. It was found that, for glycerol, the measured film thickness is somewhat lower than numerical predictions for both lubrication conditions. It is suggested that a combination of thermal effects and the hygroscopic nature of glycerol may cause the lubricant viscosity to drop resulting in thinner films than those predicted for fully flooded contacts. Starvation occurs above a critical entrainment speed and results in considerably thinner films than predicted by fully flooded I-EHL theory. A numerical study has been carried out to determine the effect of the observed starvation on film thickness. Predicted, starved film thickness values agree well with those obtained experimentally. 2010 Elsevier Ltd.
Date Issued
2010
Citation
Tribology International, 2010, 43 (11), pp.1960-1969
ISSN
0301-679X
Publisher
Elsevier Ltd
Start Page
1960
End Page
1969
Journal / Book Title
Tribology International
Volume
43
Issue
11
Copyright Statement
Copyright © 2010 Elsevier Ltd. NOTICE: this is the author’s version of a work that was accepted for publication in Tribology International. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Tribology International, 43(11), 2010. DOI:10.1016/j.triboint.2010.03.013
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000282924900002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Film thickness
Calibration
Errors
Fluorescence
Glass
Glass lasers
Glycerol
Laser produced plasmas
Lubrication
Organic polymers
Publication Status
Published