Campus C 6.3
Saarbrücken D-66123
Tel: +49 681 302 57453
Fax: +49 681 302 57454

Contact Mechanics Challenge

We call for a modeling competition in contact mechanics and invite theorists and modelers alike to make predictions on a mathematically well-defined problem.

The problem can be specified as follows:
- linear elasticity and small-slope approximation
- short range adhesion
- self-affine rough surface, topography provided numerically in real space and in Fourier space.

Participants are asked to make predictions that we can test by solving the problem numerically. You can participate by sending your predictions in a PDF by e-mail. Details on how to submit are stated in the link provided below.

A list of acceptable target quantities will be given explicitly. It includes:
- distribution of contact patch sizes, interfacial pressure and interfacial separation at a reference load
- load dependence of interfacial separation and contact stiffness
- dependence of contact area and interfacial separation on Tabor coefficient (range of adhesion)
Other experimentally measurable and physically meaningful quantities may be submitted for comparison, if a method provides additional information. However, no guarantee is given that we can consider the data or run pertinent simulations for comparison.

To give participants a good start, we will state the contact area and the mean interfacial separation at a reference load.

The brute-force numerical solution of the problem is quite involved and necessitates a large computer. The cross-sectional view of a simulation pertaining to the competition reveals the (numerical) complexity of the problem. The simulation is based on a system consisting of 64k times 64k (= 4 billion) surface points conducted at the Jülich Supercomputing Centre.

The competition will start on December 1st, 2015. Instructions and links to the exact problem definition will be given on this web page. The competition will be open for 6 months until May 31, 2016. An extension is given for another month to June 30, 2016.

If your simulations are deemed successful (committee: Prof. Martin Müser, Prof. Jim Greenwood, Prof. Wilfred Tysoe, and Prof. Nicholas Spencer), we offer to present your data in a publication in Tribology Letters. If you agree to having your data disseminated and if you agree to our write-up, you will be offered co-authorship. If you disagree, we will not use your data.

Important links/downloads

- Detailed information on the contact mechanics competition
- Surface in various representations
- Hints for experimentalists on how to rescale parameters

Selected results from reference calculations (posted May 26, 2017):
- fig04GFMD.dat
- fig05GFMD.dat
- fig10GFMD.dat
- fig12GFMD.dat