ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Numerical calculation of normal stresses in the contact area of self-affine fractal surfaces

Date: 18.08.2008
Place: ICAMS, Raum 1103

Surface roughness has a huge impact on many phenomena in tribology. In this talk I present an efficient numerical method to study the non-adhesive, frictionless, normal contact between an elastic half-space and a rigid, self-affine fractal surface. A Conjugate Gradient Method (CGM) is applied to solve a set of linear equation for unknown normal stresses. In each iteration of the CGM, a Fourier accelerated summation scheme was used. A parallel code was implemented for a Shared Memory Supercomputer, and simulations with up to 4096 times 4096 grid points were run in reasonable time (about one hour). I will compare the numerical results with a recently derived multiscale contact theory (Persson BNJ, 2001. J. Chem. Phys. 115 , 3810). The simulations show that the results are only accurate enough for not to rough surfaces and that there are still some statistical fluctuations, which prevent a detailed comparison with the multiscale contact theory.

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