Mapování tloušťky v kontaktech mazaných hovězím sérem

MAPPING OF FILM THICKNESS IN BOVINE SERUM LUBRICATED CONTACTS

článek v časopise - ostatní, Jost

en

The aim of this study is to perform detail experimental mapping of the lubricating film thickness of bovine serum (BS) within the contact between an artificial metal or ceramic femoral head and a glass disc and analyze effect of proteins on the film formation. Mapping of the lubricating film of various concentrations of BS solutions was carried out using an optical test rig. Chromatic interferograms were recorded with a high-speed digital camera and evaluated with thin film colorimetric interferometry. The film thickness was studied as a function of both time and mean speed. The results showed that film thickness increases with time for both the metal and ceramic heads. Films formed at the end of measurements with the metal head were found to be typically in the range of 60–100 nm for all BS solutions and were independent on the amount of proteins in tested fluids. At the beginning of the speed measurements, BS of all concentrations forms a very thin film (1–2 nm) and its thickness increases with increasing mean speed. However, when the speed was decreased, the film thickness did not reduce but increased with decreasing speeds that supports the findings of other researchers. Moreover, it was found that BS supply is sensitive parameter. When the lubricant reservoir below tested head was used then the measured central film thicknesses achieved values only about 20 nm, whereas when the tests were realized without the reservoir, measured central film thicknesses achieved higher values about 100 nm. For both types of the experiments, distribution of the film thickness within the contact zone is not homogeneous and two different film thickness regions can be found; thicker protein film and thinner base film that both increase with time and speed.

Článek se zabývá experimentálním studiem tloušťky mazacího filmu v kontaktech, které jsou mazány hovězím sérem. Zaměřuje se zejména na vliv koncentrace proteinů v hovězím séru.

The aim of this study is to perform detail experimental mapping of the lubricating film thickness of bovine serum (BS) within the contact between an artificial metal or ceramic femoral head and a glass disc and analyze effect of proteins on the film formation. Mapping of the lubricating film of various concentrations of BS solutions was carried out using an optical test rig. Chromatic interferograms were recorded with a high-speed digital camera and evaluated with thin film colorimetric interferometry. The film thickness was studied as a function of both time and mean speed. The results showed that film thickness increases with time for both the metal and ceramic heads. Films formed at the end of measurements with the metal head were found to be typically in the range of 60–100 nm for all BS solutions and were independent on the amount of proteins in tested fluids. At the beginning of the speed measurements, BS of all concentrations forms a very thin film (1–2 nm) and its thickness increases with increasing mean speed. However, when the speed was decreased, the film thickness did not reduce but increased with decreasing speeds that supports the findings of other researchers. Moreover, it was found that BS supply is sensitive parameter. When the lubricant reservoir below tested head was used then the measured central film thicknesses achieved values only about 20 nm, whereas when the tests were realized without the reservoir, measured central film thicknesses achieved higher values about 100 nm. For both types of the experiments, distribution of the film thickness within the contact zone is not homogeneous and two different film thickness regions can be found; thicker protein film and thinner base film that both increase with time and speed.

náhrada kyčelního kloubu, hlavice náhrady, hovězí sérum, formování proteinů, mazání, tloušťka mazacího filmu, kolorimetrická interferometrie

artificial hip joint, femoral head, bovine serum, protein formation, lubrication, film thickness, colorimetric interferometry

2013

15.04.2013

Association for Engineering Mechanics

Praha

1802-1484

20

1

27–41

15