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B. Scheichl, F. S. Guerrieri Paleotti:
"Elasto-Hydrodynamic Lubrication of Rough Contacts: On a Rigorous Generalisation of the Homogenisation Approach";
Talk: 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012), University of Vienna; 2012-09-10 - 2012-09-14; in: "CD-ROM Proceedings of the 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012), September 10-14, 2012, Vienna, Austria", J. Eberhardsteiner, H. J. Böhm, F. G. Rammerstorfer (ed.); Vienna University of Technology, Austria (2012), ISBN: 978-3-9502481-9-7; 4807-1 - 4807-20.

The rigorous theory of elasto-hydrodynamic lubrication of rough contacts based on homogenisation techniques is extended with the aim to include (i) the presence of not only wetted but also isolated dry contact regions, (ii) the deformation of the single asperity spikes, and (iii) periodic or even quasi-periodic roughness patterns involving several scales. The typical asymptotic two-scale approach proves sufficient to cope with these effects, but the complexity of the problem is considerably increased. Aspect (i) essentially affects the central homogenised problem as free boundaries separate the dry islands from the lubrication gap, filled with liquid/cavitating lubricant. Issue (ii) introduces a further coupling between the scales as it modifies the lowest-order problem governing the small-scale variation of the contact pressure due to roughness. The generalisation addressed by (iii) requires a non-standard averaging as a large-scale modulation of the roughness waviness is considered. The homogenised quantities are advantageously non-dimensional with the semi-axes of the contact ellipse and the reference pressure of Hertzian contact. A numerical case study accompanies the analysis.

elasto-hydrodynamics, homogenisation methods, surface roughness, tribology

http://publik.tuwien.ac.at/files/PubDat_208216.pdf