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rough surfaces

Two-dimensional finite element analysis of elastic adhesive contact of a rough surface

Submitted by rharish on

Adhesive contact of a rigid flat surface with an elastic substrate having Weierstrass surface profile is numerically analyzed using the finite element method. In this work, we investigate the relationship between load and contact area spanning the limits of non-adhesive normal contact to adhesive contact for various substrate material properties, surface energy and roughness parameters. In the limit of non-adhesive normal contact, our results are consistent with published work.

A comment on "A dimensionless measure for adhesion and effects of the range of adhesion in contacts of nominally flat surfaces" by M. H. Muser

Submitted by Mike Ciavarella on

I attach a Letter I sent to the Editor of a tribology journal, concerning adhesion of rough surfaces. 

I contend that some "criteria" that have been proposed based on extrapolation of numerical results are due to the limitations in present numerical sophisticated rough contact simulations, which only span at most 3 orders of magnitude of wavelengths, so typically people simulate from nanometer to micrometer scale.

A very simple estimate of adhesion of hard solids with rough surfaces based on a bearing area model

Submitted by Mike Ciavarella on

"A very simple estimate of adhesion of hard solids with rough surfaces based on a bearing area model" is in press in Meccanica, can be viewed at http://rdcu.be/s0lV Abstract In the present note, we suggest a single-line equation estimate for adhesion between elastic(hard) rough solids with Gaussian multiple scales of roughness.

a couple of recently published papers in contact mechanics -- roughness and dynamic rolling

Submitted by Mike Ciavarella on

For those interested in a classical subject like contact mechanics, here are a couple of recent papers published in August.  One is an extension of the Greenwood Williamson theory of rough contact, and the other is a linear perturbation solution of the classical Carter rolling contact problem for a rolling cylinder, when the surface is corrugated and hence there are oscillations in both normal and tangential loads.

Contact mechanics of rough surfaces: is Persson's theory better than Greenwood & Willamson?

Submitted by Mike Ciavarella on

A recent string of papers originated from Persson's paper in the physics literature contain a number of interesting new ideas, but compare, of the many theories for randomly rough surfaces, only Persson's and Bush et al, BGT. These papers often assume the original Greenwood and Williamson (GW) theory [1] to be inaccurate, but unfortunately do not test it, assuming BGT to be its better version. The original GW however is, I will show below, still the best paper and method today (not surprisingly, as not many papers have the level of 1300 citations), containing generally less assumptions than any other model, including the constitutive equation which does not need to be elastic! I just submitted this Letter to the Editor: On "Contact mechanics of real vs. randomly rough surfaces: A Green's function molecular dynamics study" by C. Campaña and M. H. Müser, EPL, 77 (2007) 38005. C. Campaña and M. H. Müser also make several questionable statements, including a dubious interpretation of their own results, and do not even cite the original GW paper; hence, we find useful to make some comments.