Part of the friction between two rough surfaces is due to the interlocking between asperities on opposite surfaces. In order for the surfaces to slide relative to each other, these interlocking asperities have to deform plastically. Here, we study the unit process of plastic ploughing of a single micrometer-scale asperity by means of two-dimensional dislocation dynamics simulations. Plastic deformation is described through the generation, motion, and annihilation of edge dislocations inside the asperity as well as in the subsurface. We find that the force required to plough an asperity at different ploughing depths follows a Gaussian distribution. For self-similar asperities, the friction stress is found to increase with the inverse of size. Comparison of the friction stress is made with other two contact models to show that interlocking asperities that are larger than ∼2 μm are easier to shear off plastically than asperities with a flat contact.
Plastic Ploughing of a Sinusoidal Asperity on a Rough Surface
Contributed by the Applied Mechanics Division of ASME for publication in the JOURNAL OF APPLIED MECHANICS. Manuscript received November 21, 2014; final manuscript received December 30, 2014; published online June 3, 2015. Editor: Yonggang Huang.
Song, H., Dikken, R. J., Nicola, L., and Van der Giessen, E. (July 1, 2015). "Plastic Ploughing of a Sinusoidal Asperity on a Rough Surface." ASME. J. Appl. Mech. July 2015; 82(7): 071006. https://doi.org/10.1115/1.4030318
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