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Modeling the real contact area plays a key role in every tribological process, such as friction, adhesion, and wear. Contact between two solids does not necessarily occur everywhere within the apparent contact area. Considering the multiscale nature of roughness, Persson proposed a theory of contact mechanics for a soft and smooth solid in contact with a rigid rough surface. In this theory, he assumed that the vertical displacement on the soft surface could be approximated by the height profile of the substrate surface. Although this assumption gives an accurate pressure distribution at the interface for complete contact, when no gap exists between two surfaces, it results in an overestimation of elastic energy stored in the material for partial contact, which typically occurs in many practical applications. This issue was later addressed by Persson by including a correction factor obtained from the comparison of the theoretical results with molecular dynamics simulation. This paper proposes a different approach to correct the overestimation of vertical displacement in Persson’s contact theory for rough surfaces with self-affine fractal properties. The results are compared with the correction factor proposed by Persson. The main advantage of the proposed method is that it uses physical parameters such as the surface roughness characteristics, material properties, sliding velocity, and normal load to correct the model. This method is also implemented in the theory of rubber friction. The results of the corrected friction model are compared with experiments. The results confirm that the modified model predicts the friction coefficient as a function of sliding velocity more accurately than the original model.


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Asperity-based modification on theory of contact mechanics and rubber friction for self-affine fractal surfaces

Show Author's information Anahita EMAMI1( )Seyedmeysam KHALEGHIAN1Saied TAHERI2
Texas State University, 601 University Drive, San Marcos, Texas 78666, USA
Virginia Polytechnic Institute and State University, 460 Old Turner Street Blacksburg, Blacksburg, Virginia 24061, USA

Abstract

Modeling the real contact area plays a key role in every tribological process, such as friction, adhesion, and wear. Contact between two solids does not necessarily occur everywhere within the apparent contact area. Considering the multiscale nature of roughness, Persson proposed a theory of contact mechanics for a soft and smooth solid in contact with a rigid rough surface. In this theory, he assumed that the vertical displacement on the soft surface could be approximated by the height profile of the substrate surface. Although this assumption gives an accurate pressure distribution at the interface for complete contact, when no gap exists between two surfaces, it results in an overestimation of elastic energy stored in the material for partial contact, which typically occurs in many practical applications. This issue was later addressed by Persson by including a correction factor obtained from the comparison of the theoretical results with molecular dynamics simulation. This paper proposes a different approach to correct the overestimation of vertical displacement in Persson’s contact theory for rough surfaces with self-affine fractal properties. The results are compared with the correction factor proposed by Persson. The main advantage of the proposed method is that it uses physical parameters such as the surface roughness characteristics, material properties, sliding velocity, and normal load to correct the model. This method is also implemented in the theory of rubber friction. The results of the corrected friction model are compared with experiments. The results confirm that the modified model predicts the friction coefficient as a function of sliding velocity more accurately than the original model.

Keywords: tribology, surface roughness, contact area, rubber friction, self-affine fractals

References(50)

[1]
Müser M H, Dapp W B, Bugnicourt R, Sainsot P, Lesaffre N, Lubrecht T A, Persson B N, Harris K, Bennett A, Schulze K J T L. Meeting the contact-mechanics challenge. Tribol Lett 65(4): 118 (2017)
[2]
Hertz H. Über die berührung fester elastischer kǒrper. (in Germany). Journal für die reine und angewandte Mathematik 92: 156–171(1881)
[3]
Greenwood J A, Williamson J P. Contact of nominally flat surfaces. Proc Roy Soc Lond Math Phys Sci 295(1442): 300–319(1966)
[4]
McCool J I. Comparison of models for the contact of rough surfaces. Wear 107(1): 37–60(1986)
[5]
Greenwood J. A simplified elliptic model of rough surface contact. Wear 261(2): 191–200(2006)
[6]
Ciavarella M, Greenwood J, Paggi M. Inclusion of “interaction” in the Greenwood and Williamson contact theory. Wear 265(5): 729–734(2008)
[7]
Ciavarella M, Delfine V, Demelio G. A “re-vitalized” Greenwood and Williamson model of elastic contact between fractal surfaces. J Mech Phys Solids 54(12): 2569–2591(2006)
[8]
Carbone G. A slightly corrected Greenwood and Williamson model predicts asymptotic linearity between contact area and load. J Mech Phys Solids 57(7): 1093–1102(2009)
[9]
Bush A, Gibson R, Thomas T. The elastic contact of a rough surface. Wear 35(1): 87–111(1975)
[10]
Zavarise G, Borri-Brunetto M, Paggi M. On the resolution dependence of micromechanical contact models. Wear 262(1–2): 42–54(2007)
[11]
Archard J. Elastic deformation and the laws of friction. P Roy Soc A-Math Phy 243 (1233): 190–205(1957)
[12]
Persson B N. Theory of rubber friction and contact mechanics. J Chem Phys 115(8): 3840–3861(2001)
[13]
Paggi M, Ciavarella M J W. The coefficient of proportionality κ between real contact area and load, with new asperity models. Wear 268(7–8): 1020–1029(2010)
[14]
Ciavarella M, Murolo C, Demelio G. On the elastic contact of rough surfaces: numerical experiments and comparisons with recent theories. Wear 261(10): 1102–1113(2006)
[15]
Yastrebov V A, Anciaux G, Molinari J-F. From infinitesimal to full contact between rough surfaces: evolution of the contact area. Int J Solids Struct 52: 83–102(2015)
[16]
Yang C, Persson B. Contact mechanics: Contact area and interfacial separation from small contact to full contact. Phys-Condens Mat 20(21): 215214 (2008)
[17]
Dapp W B, Prodanov N, Müser M H. Systematic analysis of Persson’s contact mechanics theory of randomly rough elastic surfaces. Phys-Condens Mat 26(35): 355002 (2014)
[18]
Feder J. Fractals. New York (US): Plenum Press, 1988.
[19]
Majumdar A, Bhushan B. Role of fractal geometry in roughness characterization and contact mechanics of surfaces. ASME J Tribol 112(2): 205–216(1990)
[20]
Majumdar A, Bhushan B. Fractal model of elastic-plastic contact between rough surfaces. ASME J Tribol 113(1): 1–11(1991)
[21]
Majumdar A, Tien C. Fractal characterization and simulation of rough surfaces. Wear 136(2): 313–327(1990)
[22]
Klüppel M, Heinrich G. Rubber friction on self-affine road tracks. Rubber Chem Technol 73(4): 578–606(2000)
[23]
Heimann B, Wriggers P, Klüppel M, Besdo D, Nackenhorst U, Kröger M. Elastomere friction: theory, experiment and simulation. Berlin (Germany): Springer Science & Business Media, 2010.
[24]
Gnecco E, Meyer E. Fundamentals of Friction and Wear on the Nanoscale. Berlin (Germany): Springer, 2007.
[25]
Sun L. Structural Behavior of Asphalt Pavements: Intergrated Analysis and Design of Conventional and Heavy Duty Asphalt Pavement. Oxford (UK): Butterworth-Heinemann, 2016.
[26]
Persson B. On the fractal dimension of rough surfaces. Tribol Lett 54(1): 99–106(2014)
[27]
Heinrich G. Hysteresis friction of sliding rubbers on rough and fractal surfaces. Rubber Chem Technol 70(1): 1–14(1997)
[28]
Persson B. Adhesion between an elastic body and a randomly rough hard surface. Eur Phys J E 8(4): 385–401(2002)
[29]
Zilberman S, Persson B. Adhesion between elastic bodies with rough surfaces. Solid state commun 123(3–4): 173–177(2002)
[30]
Persson B, Albohr O, Tartaglino U, Volokitin A, Tosatti E. On the nature of surface roughness with application to contact mechanics, sealing, rubber friction and adhesion. Phys-Condens Mat 17(1): R1 (2004)
[31]
Manners W, Greenwood J. Some observations on Persson’s diffusion theory of elastic contact. Wear 261(5–6): 600–610(2006)
[32]
Scaraggi M, Persson B N. General contact mechanics theory for randomly rough surfaces with application to rubber friction. J Chem Phys 143(22): 224111 (2015)
[33]
Motamedi M, Taheri S, Sandu C, Legrand P. Characterization of road profiles based on fractal properties and contact mechanics. Rubber Chem Technol 90(2): 405–427(2017)
[34]
Persson B N. Contact mechanics for randomly rough surfaces. Surf Sci Rep 61(4): 201–227(2006)
[35]
Timoshenko S, Goodier J. Theory of Elasticity. New York (US): McGraw-Hill Book Company. Inc., 1951.
[36]
Hongyan C, Ran A, Ligang C. Applicability of the Hertz contact theory to rolling rubber cylinders model. Int J Mech Eng Appl 4(6): 242–248(2016)
[37]
Lorenz B, Persson B, Dieluweit S, Tada T. Rubber friction: Comparison of theory with experiment. Eur Phys J E 34(12): 129 (2011)
[38]
Scaraggi M, Persson B. Friction and universal contact area law for randomly rough viscoelastic contacts. Phys-Condens Mat 27(10): 105102 (2015)
[39]
Kärkimaa J, Tuononen A. Experimental study on velocity and temperature dependency of rubber-asphalt friction. The Dynamics of Vehicles on Roads and Tracks: Proceedings of the 24th Symposium of the International Association for Vehicle System Dynamics), Graz, Austria, 2016: 17-21.
[40]
Emami A, Khaleghian S, Su C, Taheri S. Physics-based friction model with potential application in numerical models for tire-road traction. Dynamic Systems and Control Conference, American Society of Mechanical Engineers, Tysons Corner, Virginia, US, 2017, DOI .
DOI
[41]
Lang A, Klüppel M. Influences of temperature and load on the dry friction behaviour of tire tread compounds in contact with rough granite. Wear 380: 15–25(2017)
[42]
Fina E, Gruber P, Sharp R. Hysteretic rubber friction: Application of Persson’s theories to Grosch’s experimental results. J Appl Mech 81(12): 121001 (2014)
[43]
Sharp R, Gruber P, Fina E. Circuit racing, track texture, temperature and rubber friction. Vehicle Syst Dyn 54(4): 510–525(2016)
[44]
Lorenz B, Oh Y, Nam S, Jeon S, Persson B. Rubber friction on road surfaces: Experiment and theory for low sliding speeds. J Chem Phys 142(19): 194701 (2015)
[45]
Tiwari A, Miyashita N, Espallargas N, Persson B. Rubber friction: The contribution from the area of real contact. J Chem Phys 148(22): 224701 (2018)
[46]
Emami A, Khaleghian S, Bezek T, Taheri S. Design and development of a new test setup to study friction and wear for indoor and outdoor tracks. P I Mech Eng J-J Eng 234(5): 730–742(2020)
[47]
Iwai T, Uchiyama Y. The strain generated on a rubber surface in the course of pattern abrasion. Tire Sci Technol 28(2): 96–105(2000)
[48]
Motamedi M. Road surface measurement and multi-scale modeling of rubber road contact and adhesion. Ph.D Thesis. Blacksburg (US): Virginia Tech, 2015.
[49]
Bugnicourt R, Sainsot P, Lesaffre N, Lubrecht A. Transient frictionless contact of a rough rigid surface on a viscoelastic half-space. Tribol Int 113: 279–285(2017)
[50]
Afferrante L, Bottiglione F, Putignano C, Persson B, Carbone G J T L. Elastic contact mechanics of randomly rough surfaces: An assessment of advanced asperity models and Persson’s theory. Tribol Lett 66(2): 1–13(2018)
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Publication history

Received: 17 June 2019
Revised: 28 January 2020
Accepted: 07 January 2021
Published: 15 May 2021
Issue date: December 2021

Copyright

© The author(s) 2021

Acknowledgements

The authors would like to thank the industry advisory board (IAB) members of the Center for Tire Research (CenTiRe) for their financial support and Sumitomo Rubber Industries (SRI) and Bridgestone Americas Operations for providing the rubber samples and their dynamic modulus master curves.

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