eprintid: 1999
rev_number: 7
eprint_status: archive
userid: 56
dir: disk0/00/00/19/99
datestamp: 2013-12-02 12:56:31
lastmod: 2014-10-09 09:20:24
status_changed: 2013-12-02 12:56:31
type: article
metadata_visibility: show
creators_name: Paggi, Marco
creators_name: Barber, J.R.
creators_id: marco.paggi@imtlucca.it
creators_id: 
title: Contact conductance of rough surfaces composed of modified RMD patches 
ispublished: pub
subjects: TJ
divisions: CSA
full_text_status: none
keywords: Contact conductance; Contact stiffness; Fractal surfaces;  Roughness; Waviness; Numerical methods
abstract: The dependence of the contact conductance of self-affine rough surfaces on the applied pressure is studied using the electric-mechanical analogy which relates the contact conductance to the normal stiffness. According to dimensional analysis arguments, an efficient dimensionless formulation is proposed which minimizes the number of dimensionless variables governing the phenomenon. Assuming incomplete similarity in the dimensionless pressure, a power-law dependence between contact conductance and mean pressure is proposed. This is confirmed by earlier semi-empirical correlations that are recovered as special cases of the proposed formulation. To compute the exponent β of the power-law, and relate it to the morphological properties of the surfaces, we numerically test self-affine rough surfaces composed of random midpoint displacement (RMD) patches. Such patches are generated using a modified {RMD} algorithm in order to decouple the effect of the long wavelength cut-off from that due to microscale roughness. Numerical results show that the long wavelength cut-off has an important effect on the contact conductance, whereas the sampling interval and the fractal dimension are less important. The effect of elastic interaction between asperities has also been quantified and it significantly influences the predicted power-law exponent β. 
date: 2011
date_type: published
publication: International Journal of Heat and Mass Transfer
volume: 54
number: 21–22
publisher: Elsevier
pagerange: 4664 - 4672
id_number: 10.1016/j.ijheatmasstransfer.2011.06.011
refereed: TRUE
issn: 0017-9310
official_url: http://www.sciencedirect.com/science/article/pii/S0017931011003334
citation:   Paggi, Marco and Barber, J.R.  Contact conductance of rough surfaces composed of modified RMD patches.  International Journal of Heat and Mass Transfer, 54 (21–22).  4664 - 4672.  ISSN 0017-9310      (2011)