The effect of normal force and roughness on friction in human finger contact

Tomlinson, Sarah; Lewis, Roger; Carré, Matt

doi:10.1016/j.wear.2008.12.084

Cited by 105 publications

(102 citation statements)

References 14 publications

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“…The effects of a number of parameters on finger friction, have been investigated previously, for example, load [1][2][3], surface textures, different materials, contact area, and moisture (for more details see the reviews of finger and skin tribology in references [4] and [5]. "Real" contact area is perhaps the biggest influencing factor on finger friction and this is affected significantly by the parameters mentioned above.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Friction Mechanisms Between the Human Finger and Flat Contacting Surfaces in Moist Conditions

et al. 2010

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Human hands sweat in different circumstances and the presence of sweat can alter the friction between the hand and contacting surface. It is therefore important to understand how hand moisture varies between people, during different activities and the effect of this on friction.In this study a survey of fingertip moisture was done. Friction tests were then carried out to investigate the effect of moisture.Moisture was added to the surface of the finger, the finger was soaked in water, and water was added to the counter-surface; the friction of the contact was then measured. It was found that the friction increased, up until a certain level of moisture and then decreased. The increase in friction has previously been explained by viscous shearing, water absorption and capillary adhesion. The results from the experiments enabled the mechanisms to be investigated analytically. This study found that water absorption is the principle mechanism responsible for the increase in friction, followed by capillary adhesion, although it was not conclusively proved that this contributes significantly. Both these mechanisms increase friction by increasing the area of contact and therefore adhesion. Viscous shearing in the liquid bridges has negligible effect. There are, however, many limitations in the modelling that need further exploration.

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Section: Introductionmentioning

confidence: 99%

Understanding the Friction Mechanisms Between the Human Finger and Flat Contacting Surfaces in Moist Conditions

et al. 2010

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“…Capillary adhesion, through the formation of fluid menisci between the contacting surfaces, may in some cases contribute to the overall adhesion [31]. Notable exceptions where friction mechanisms other than adhesion play a more significant additional role are when the skin is very wet with a fluid film on the surface, where hydrodynamic lubrication can occur [7,[32][33][34], and ridged-skin friction against very rough surfaces, where friction due to ploughing or deformation of the skin ridges by relatively hard roughness asperities can occur [35][36][37][38]. In the current work, there were no finger ridges present and the surface of the steel ring in contact with the human and synthetic skin was relatively smooth (R a 0.29 µm), so that the ploughing/deformation friction mechanism is unlikely to be significant.…”

Section: Effect Of Dry or Moist Skin Conditionsmentioning

confidence: 99%

Comparison of the Friction Behavior of Occluded Human Skin and Synthetic Skin in Dry and Moist Conditions

Franklin

Baranowska

Hendriks

et al. 2016

Tribology Transactions

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The goal of this work was to assess the suitability of a commercial synthetic skin to simulate occluded human skin friction behaviour in dry and moist skin conditions and under different applied surface pressures, with the view to using this material as a tribological test-bed for healthcare and personal care devices that are in direct contact with the skin during use. A flat rotating ring friction measurement device, in which one part of the skin surface is continuously covered (i.e. occluded), was used to compare the friction behaviour of human skin and the synthetic skin in controlled nominally dry and nominally moist skin conditions. Three loading levels were tested, simulating light, medium and high skin pressures typical of many lifestyleand personal health-related applications. The results showed that the friction behaviour of the synthetic skin tested here was notably different to that of human skin in vivo in terms of the effects of skin hydration, sliding time and applied surface pressure. It is concluded that, for use as a tribological test-bed, the tested synthetic skin model does not provide an acceptable alternative to in vivo tests using human skin.

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“…The contact mechanics is influenced by the material and microgeometry of both the surfaces in contact, skin hydration, normal load and the relative velocity of the surfaces in contact. Finger pad friction properties were measured against a wide range of materials so far such as packaging materials [3], textiles [4,5],metals [6][7][8], polymers [6,8] and glass [9,10] to name a few. The effect of the interacting surface's microgeometry on finger friction has been explored in studies on ridged surfaces with different ridge geometries to understand their effect on finger friction [7,11].…”

Section: Introductionmentioning

confidence: 99%

“…The effect of applied variables like normal force, sliding velocity and lubricants on finger pad friction has also been well characterized [6,8,14]. Inherent skin related phenomena like occlusion, sweating and the sensitivity of coefficient of friction to these conditions were well investigated [9,10].…”

Section: Introductionmentioning

confidence: 99%

Investigation of friction mechanisms in finger pad sliding against surfaces of varying roughness

Chimata

Schwartz

2015

Biotribology

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Human finger pad friction and the effects of surface features on the fingerprint ridges, shape of the finger and the material properties of the finger were investigated. The friction coefficients for three fine-grit abrasive papers were measured to assess these effects. Four probing surfaces were used: human index finger pad, silicone replicas of the finger with and without fingerprints, and a smooth silicone sphere. Friction tests were performed at a constant normal load of 0.5 N in two probe orientations: normal and perpendicular to the orientation of the fingerprint ridges. Scanning electron microscopy of the abrasive papers was performed to examine their surface topography. Based on the trends in coefficients of friction, topography of the abrasive papers, surface features of the finger pad, and the shape and elastic properties of the finger, possible friction mechanisms were discussed. It was inferred that the change in the shape of the probe (from a sphere to the finger shape) changes the adhesion and deformation components of friction, the presence of fingerprints adds an interlocking contribution to the friction and decrease the adhesion and deformation components of friction, and the elastic properties of the finger lead to an increase in all the three components of friction.Keywords skin tribology, finger pad friction, friction mechanisms, fingerprints, tactility, haptics Disciplines Applied Mechanics | Other Mechanical Engineering | TribologyComments NOTICE: this is the author's version of a work that was accepted for publication in Biotribiology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Biotribiology, vol. 3 (2015) NOTICE: this is the author's version of a work that was accepted for publication in Biotribiology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document.Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Biotribiology, vol. 3 (2015) AbstractHuman finger pad friction and the effects of surface features on the fingerprint ridges, shape of the finger and the material properties of the finger were investigated. The friction coefficients for three fine-grit abrasive papers were measured to assess these effects. Four probing surfaces were used:human index finger pad, silicone replicas of the finger with and without fingerprints, and a smooth silicone sphere. Friction tests were performed at a constant normal load of 0.5 N in two probe orientations: normal and perpendicular to the orientation of the fingerprint ridges. Scanning electron microscopy of the abrasive papers was performed to examine thei...

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The effect of normal force and roughness on friction in human finger contact

Cited by 105 publications

References 14 publications

Understanding the Friction Mechanisms Between the Human Finger and Flat Contacting Surfaces in Moist Conditions

Understanding the Friction Mechanisms Between the Human Finger and Flat Contacting Surfaces in Moist Conditions

Comparison of the Friction Behavior of Occluded Human Skin and Synthetic Skin in Dry and Moist Conditions

Investigation of friction mechanisms in finger pad sliding against surfaces of varying roughness

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