The area of molecular contact between surfaces plays a central role in friction and adhesion. Traditionally it is calculated using continuum contact mechanics, which is known to break down as the contact width approaches atomic dimensions. Yet contact mechanics is being applied at ever smaller lengths, even to atomic force microscope (AFM) tips containing a few atoms. Molecular simulations are used to test the limits of contact mechanics under ideal non-adhesive and adhesive conditions. A simple geometry of sphere-on-flat is considered. One surface is an atomically flat crystal and is deformable. The approximately spherical curved surface is rigid and is produced by bending a crystal, or cutting a crystal or amorphous material. While these methods of producing the curved surface differ only in the amount of atomic-scale roughness, they produce very different behavior in some quantities. The normal stiffness is affected very little, the contact area can be modified by a factor of two, and the friction and lateral stiffness can be modified by an order of magnitude. The implications for AFM experiments are discussed.
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World Tribology Congress III
September 12–16, 2005
Washington, D.C., USA
Conference Sponsors:
- Tribology Division
ISBN:
0-7918-4201-0
PROCEEDINGS PAPER
When Does Continuum Theory Describe Mechanical Contacts?
Binquan Luan,
Binquan Luan
Johns Hopkins University, Baltimore, MD
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Mark Robbins
Mark Robbins
Johns Hopkins University, Baltimore, MD
Search for other works by this author on:
Binquan Luan
Johns Hopkins University, Baltimore, MD
Mark Robbins
Johns Hopkins University, Baltimore, MD
Paper No:
WTC2005-64095, pp. 407-408; 2 pages
Published Online:
November 17, 2008
Citation
Luan, B, & Robbins, M. "When Does Continuum Theory Describe Mechanical Contacts?." Proceedings of the World Tribology Congress III. World Tribology Congress III, Volume 1. Washington, D.C., USA. September 12–16, 2005. pp. 407-408. ASME. https://doi.org/10.1115/WTC2005-64095
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