Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Does Linearity Always Hold between Friction Force and Real Contact Area: An Experimental Study

Version 1 : Received: 7 June 2021 / Approved: 8 June 2021 / Online: 8 June 2021 (10:36:15 CEST)

A peer-reviewed article of this Preprint also exists.

Journal reference: Scientific Reports | (2021) 2021, 11, 20366
DOI: 10.1038/s41598-021-99909-2


Classical laws of friction suggest that friction force is proportional to the normal load and independent of the nominal contact area. As a great improvement in this subject, it is now widely accepted that friction force is proportional to the real area in contact, and much work has been conducted based on this hypothesis. In present study, this hypothesis will be carefully revisited by measuring the friction force and real contact area in-site and real-time at both normal loading and unloading stages. Our experiments reveal that the linear relation always holds between friction force and normal load. However, for the relation between friction force and real contact area, the linearity holds only at the loading stage while fails at the unloading stage. This study may improve our understanding of the origin of friction.


Friction Force; Real Contact Area; Rough Surface


ENGINEERING, Automotive Engineering

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