Fundamentals of Friction

In a very wide variety of situations friction closely follows two laws generally known as Amontons Laws. These state that - 

In fact both laws were recognised by Leonardo da Vinci about the end of the 15th century, but like most of his scientific work remained unknown until the 19th century. They were only re-discovered by Amontons about two hundred years later, and were then proved by Coulomb a further eighty years later, in 1781. 

The second law leads to the concept of a coefficient of friction, since, if the friction force is proportional to the load, then 

Where one or both of the contacting surfaces becomes permanently deformed during sliding, the energy required to produce the deformation represents an additional component of the friction force. For engineering surfaces the amount of permanent deformation which can be tolerated is very limited so that the deformation friction is small in comparison with the adhesive friction. Elastic deformation only makes a significant contribution to the total friction when there is a high level of hysteresis in the elastic recovery, such as in vehicle tyres, and this is not normally a consideration when molybdenum disulphide is used. For practical purposes it can therefore be assumed that adhesive friction is the only type of friction which needs to be considered. 

The yield stress p or hardness is typically about five times the critical shear stress S. The coefficient of friction will therefore be given by 

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I. L. Singer and H. M. Pollock, eds.. Fundamentals of Friction Macroscopic and Microscopic Processes, Kluwer, 1996. 

Tabor D 1992 Fundamentals of Friction ed I L Singer and FI M Pollock (London Kluwer)... 

Krim J K 1998 Fundamentals of friction MRS Bull. 20-1 (related articles in this issue of MRS Bulletin describe the status of several sub-disciplines of tribology)... 

In order to better understand the fundamentals of friction reduction by molybdenum dithiocarbamate and to relate it to chemical changes and transfer phenomena of the tribofilm, an ultrahigh vacuum (UHV, 10 7 Pa) tribometer was used (Grossiord et al., 1998 Martin et al., 1999). Specifically, this tribometer allows in situ Auger electron spectroscopy (AES), X-ray photoelectron... 

Greenwood JA (1992) Contact of rough surfaces. In Singer IL, Pollock HM (eds) Fundamentals of friction macroscopic and microscopic processes. Kluver Academic Publishers, London, p 37... 

Tabor D 1992 Friction as a dissipative prooess Fundamentals of Friction Macrosoopic and Microscopic Processes (NATO ASI Series E220) eds I L Singer and H M Pollook (Dordrecht Kluwer) pp 3-24... 

For general overviews Fundamentals of Friction Macroscopic and (Microscopic Processes , NATO AS Series, (Ed.) I.L. Singer and H.M. Pollock Kluwer Dordrecht (1992). 

Plastic zone, median/radial, and lateral cracks for moving indentor. (From Evans, A.G. and Marshall, D.B., in Fundamentals of Friction and INear of Materials, Rigney, D.A., Ed., ASME, 439, 1981. With permission.)... 

IL Singer. Solid lubrication processes. In IL Singer, HM Pollock, eds. Fundamentals of Friction Macroscopic Processes. Dordrecht Kluwer, 1992 237. 

Fundamentals of Friction Series E Applied Sciences, NATO Advanced Sciences Institutes Singer, I.L. Pollock, H.M., Eds Kluwer Academic Publishers, Dortrecht, 1992. 

Briscoe, B.J. "Friction of Polymers" in Fundamentals of Friction Macroscopic Origins , Eds. E. Singer and H. Pollack, Kluwer Academic Press, Netherlands, 1992. 

Fundamentals of friction, Singer I. L., Pollock H. M. Eds. NATO advanced Study Institute Series E Applied Sciences Plenum, New York, 1992,220,... 

Fundamentals of Friction Macroscopic and Microscopic Processes", Singer,... 

Tabor, D. In Fundamentals of Friction Macroscopic arul Microscopic Processes-, Singer, I. L. Pollocl H. M., Eds. Kluwer Academic Publishers Dordrecht, 1992, pp. 3-24. 

L.E. Samuels et al.. Sliding Wear Mechanisms, Fundamentals of Friction and Wear of Materials, D.A. Rigney, Ed., American Society for Metals, 1981, p 13-42... 

Gnecco, E. and Meyer, E. (eds) (2007) Fundamentals of Friction and Wear on the Nanoscale, Springer, Berlin. 

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