On the load-area relation in rough adhesive contacts

Salehani, Mohsen Khajeh; Dokkum, Jan Steven Van; Irani, Nilgoon; Nicola, Lucia

doi:10.1016/j.triboint.2019.106099

Cited by 8 publications

(5 citation statements)

References 26 publications

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“…For adhesiveless rough contacts, the area-load relation is known to be linear [27][28][29]. However, recent studies confirm that adhesion may lead to strong non-linearity of the F − A curve [30][31][32]. In our calculations, this is especially true for the unloading path in agreement with numerical [15] and experimental [33] findings.…”

Section: Adhesive Hysteresis and Pull-off Force: Effect Of Loading Parameterssupporting

confidence: 88%

Roughness-Induced Adhesive Hysteresis in Self-Affine Fractal Surfaces

Violano

Afferrante

2021

Lubricants

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It is known that in the presence of surface roughness, adhesion can lead to distinct paths of loading and unloading for the area–load and penetration–load relationships, thus causing hysteretic loss. Here, we investigate the effects that the surface roughness parameters have on such adhesive hysteresis loss. We focus on the frictionless normal contact between soft elastic bodies and, for this reason, we model adhesion according to Johnson, Kendall, and Roberts (JKR) theory. Hysteretic energy loss is found to increase linearly with the true area of contact, while the detachment force is negligibly influenced by the maximum applied load reached at the end of the loading phase. Moreover, for the micrometric roughness amplitude hrms considered in the present work, adhesion hysteresis is found to be affected by the shorter wavelengths of roughness. Specifically, hysteresis losses decrease with increasing fractal dimension and cut-off frequency of the roughness spectrum. However, we stress that a different behavior could occur in other ranges of roughness amplitude.

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Section: Adhesive Hysteresis and Pull-off Force: Effect Of Loading Parameterssupporting

confidence: 88%

Roughness-Induced Adhesive Hysteresis in Self-Affine Fractal Surfaces

Violano

Afferrante

2021

Lubricants

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“…Unfortunately, their calculations were conducted at an essentially fixed ratio of system size and short-wavelength cutoff (with varying roll-off wavelengths) so that small logarithmic corrections to linear relations between contact area and load may not be particularly telling. So far, the strongest support for deviations from linearity were reported in two carefully conducted simulation studies by Nicola and coworkers (van Dokkum et al, 2018;Salehani et al, 2020). They found quite remarkable logarithmic corrections to linear laws in large, one-dimensional adhesionless contacts (van Dokkum et al, 2018) as well as clearly sublinear scaling for two-dimensional, adhesive surfaces (Salehani et al, 2020).…”

Section: Introductionmentioning

confidence: 96%

“…So far, the strongest support for deviations from linearity were reported in two carefully conducted simulation studies by Nicola and coworkers (van Dokkum et al, 2018;Salehani et al, 2020). They found quite remarkable logarithmic corrections to linear laws in large, one-dimensional adhesionless contacts (van Dokkum et al, 2018) as well as clearly sublinear scaling for two-dimensional, adhesive surfaces (Salehani et al, 2020). However, the latter may have been in a regime with non-negligible adhesive hysteresis, in which case non-linearity between a r and p is unavoidable.…”

Section: Introductionmentioning

confidence: 97%

Effect of Structural Parameters on the Relative Contact Area for Ideal, Anisotropic, and Correlated Random Roughness

Zhou

Müser

2020

Front. Mech. Eng.

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The relative contact area between an initially flat, adhesion-and frictionless, linearly elastic body and a variety of rough, rigid counterbodies is studied using Green's function molecular dynamics. The indenter's height profiles range from ideal random roughness through roughness with a moderate amount of correlation to periodically repeated, single-asperity indenters having perfect phase coherence. At small reduced pressures, p * ≡ p/(E * ḡ) ≪ 1, sufficiently large systems are consistent with a linear a c = κ p * relation. Here p is the pressure, E * is the contact modulus,ḡ the root-mean-square height gradient, and κ a unitless proportionality coefficient. However, the parameterḡ must be evaluated over the real contact area for the linear relation to hold if the random roughness is correlated or the interfacial dimension reduced. No single unitless structural parameter-including the Nayak parameter-correlates in a significant fashion with κ.

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“…1(a)), assuming steady-state conditions and Amontons' microscopic friction. Although some of the issues raised here have already been addressed in line contacts [22][23][24], load-area and other relations do not generalize from line to areal contacts, neither in simple indenter geometries [25] nor in randomly rough contacts [26,27], so that the effect of roughness on the friction coefficient can differ between the two cases. More importantly, the analysis of how coupling affects leakage cannot be addressed in line contacts, since they automatically seal in the lateral (sliding) direction, while they are open in the transverse direction.…”

mentioning

confidence: 92%

Significance of Elastic Coupling for Stresses and Leakage in Frictional Contacts

Müller,

Müser,

Carbone

et al. 2023

Phys. Rev. Lett.

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We study how the commonly neglected coupling of normal and in-plane elastic response affects tribological properties when Hertzian or randomly rough indenters slide past an elastic body. Compressibility-induced coupling is found to substantially increase maximum tensile stresses, which cause materials to fail, and to decrease friction such that Amontons' law is violated macroscopically even when it holds microscopically. Confinement-induced coupling increases friction and enlarges domains of high tension. Moreover, both types of coupling affect the gap topography and thereby leakage. Thus, coupling can be much more than a minor perturbation of a mechanical contact.

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On the load-area relation in rough adhesive contacts

Cited by 8 publications

References 26 publications

Roughness-Induced Adhesive Hysteresis in Self-Affine Fractal Surfaces

Roughness-Induced Adhesive Hysteresis in Self-Affine Fractal Surfaces

Effect of Structural Parameters on the Relative Contact Area for Ideal, Anisotropic, and Correlated Random Roughness

Significance of Elastic Coupling for Stresses and Leakage in Frictional Contacts

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