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On Pastewka and Robbins' Criterion for Macroscopic Adhesion of Rough Surfaces

Mike Ciavarella's picture

On Pastewka and Robbins' Criterion for Macroscopic Adhesion of Rough Surfaces

M. Ciavarella

[+] Author and Article Information

J. Tribol 139(3), 031404 (Nov 30, 2016) (5 pages)

Paper No: TRIB-16-1057; doi: 10.1115/1.4034530

History: Received February 15, 2016; Revised July 18, 2016




Abstract | Introduction | A Simple Asperity Model | Pull-Off | Discussion | Conclusion | References

Pastewka and Robbins (2014, “Contact Between Rough Surfaces and a Criterion for Macroscopic Adhesion,” Proc. Natl. Acad. Sci., 111(9), pp. 3298–3303) recently have proposed a criterion to distinguish when two surfaces will stick together or not and suggested that it shows quantitative and qualitative large conflicts with asperity theories. However, a comparison with asperity theories is not really attempted, except in pull-off data which show finite pull-off values in cases where both their own criterion and an asperity based one seem to suggest nonstickiness, and the results are in these respects inconclusive. Here, we find that their criterion corresponds very closely to an asperity model one (provided we use their very simplified form of the Derjaguin–Muller–Toporov (DMT) adhesion regime which introduces a dependence on the range of attractive forces) when bandwidth α is small, but otherwise involves a root-mean-square (RMS) amplitude of roughness reduced by a factor α−−√α. Therefore, it implies that the stickiness of any rough surface is the same as that of the surface where practically all the wavelength components of roughness are removed except the very fine ones.


Mike Ciavarella's picture

so if anyone is interested, I can discuss privately the developments.........


Mike Ciavarella's picture

Despite these days it is impossible to talk of GW models because the "fractal" community suggests interaction and multiscale effects are completely wrong in GW, here are some GW models with adhesion which seem to work against experiments, showing the main effect of rms roughness, contrary to what the PR model says in the rush to forget all GW, that stickiness depends only on slopes and curvature

Mike Ciavarella's picture

In this new paper accepted in Trib Int we show that the deviation from PR to GW cannot be all attributed to scatter due to imperfect tails of Gaussian surfaces as easily provoqued by low fractal dimension with insufficient size of the domain

Mike Ciavarella's picture

This paper may help shed some ligth why the very numerous crude approximations in PR model may have coincidentally led to reasonable agreement in their set of parameters.   But not for any extrapolation fundamental purpose!   The paper is submitted but probably siib accepted, as reviewers were positive.

1. arXiv:1701.04300 [pdfpsother]

On the use of DMT approximations in adhesive contacts, with remarks on random rough contactsMichele CiavarellaComments: 11 pages, 5 figuresSubjects: Materials Science (cond-mat.mtrl-sci)

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