An experimental study on the relation between friction force and real contact area

Liang, Xuanming; Xing, Y. Z.; Li, L. T.; Yuan, Weike; Wang, Gangfeng

doi:10.1038/s41598-021-99909-2

Cited by 34 publications

(13 citation statements)

References 35 publications

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“…The F t was spatially resolved by capacitive sensors when rubbed against the counterbody, which was mounted on a reciprocating piezoelectric actuator. A linear correlation between F t and F N was observed (Figure S4), which appears to be in agreement with the Bowden and Tabor theory , (more information in Section S7). F t values were recorded over a stroke amplitude of 2 mm in a reciprocating mode.…”

Section: Methodssupporting

confidence: 87%

Insights into the Multiscale Lubrication Mechanism of Edible Phase Change Materials

Soltanahmadi

Bryant

Sarkar

2023

ACS Appl. Mater. Interfaces

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Investigation of a lubrication behavior of phase change materials (PCM) can be challenging in applications involving relative motion, e.g., sport (ice skating), food (chocolates), energy (thermal storage), apparel (textiles with PCM), etc. In oral tribology, a phase change often occurs in a sequence of dynamic interactions between the ingested PCM and oral surfaces from a licking stage to a saliva-mixed stage at contact scales spanning micro-(cellular), meso-(papillae), and macroscales. Often the lubrication performance and correlations across length scales and different stages remain poorly understood due to the lack of testing setups mimicking real human tissues. Herein, we bring new insights into lubrication mechanisms of PCM using dark chocolate as an exemplar at a single-papilla (meso)-scale and a full-tongue (macro) scale covering the solid, molten, and saliva-mixed states, uniting highly sophisticated biomimetic oral surfaces with in situ tribomicroscopy for the first time. Unprecedented results from this study supported by transcending lubrication theories reveal how the tribological mechanism in licking shifted from solid fat-dominated lubrication (saliva-poor regime) to aqueous lubrication (saliva-dominant regime), the latter resulted in increasing the coefficient of friction by at least threefold. At the mesoscale, the governing mechanisms were bridging of cocoa butter in between confined cocoa particles and fat coalescence of emulsion droplets for the molten and saliva-mixed states, respectively. At the macroscale, a distinctive hydrodynamic viscous film formed at the interface governing the speed-dependent lubrication behavior indicates the striking importance of multiscale analyses. New tribological insights across different stages and scales of phase transition from this study will inspire rational design of the next generation of PCM and solid particle-containing materials.

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Section: Methodssupporting

confidence: 87%

Insights into the Multiscale Lubrication Mechanism of Edible Phase Change Materials

Soltanahmadi

Bryant

Sarkar

2023

ACS Appl. Mater. Interfaces

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“…This finding is expected as the friction is fully non-linear mechanism and it depends on many parameters other than contact area such as the equivalent slip rate, the contact pressure, and the average temperature at the contact point. Also, there are several reports that indicate the nonlinear relation between friction force and the contact area [27,28]. The mechanism of the pressing load reduction in novel equal channel angular pressing is based on the change in contact area.…”

Section: Resultsmentioning

confidence: 99%

A novel equal channel angular pressing design to eliminate punch deflection and to reduce the pressing force

Abbaszadeh

Sheikhi

Fallah

et al. 2023

Materialwissenschaft Werkst

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In the present study a new design of the equal channel angular pressing die and punch is introduced. The new design eliminates the deflection of the punch and at the same time lowers the frictional forces by reducing the contact area. In order to show the capability of the new design, the Al‐7075 alloy samples were processed in two equal channel angular pressing dies. The measured data for the novel and conventional equal channel angular pressing processes were compared. The microstructure of the processed samples was examined with scanning electron microscopy and transmission electron microscopy. The results of the experimental study revealed that the novel die can fully eliminate the risk of the punch deflection and simultaneously reduce the maximum required pressing force by about 3.1 % to 9.8 % for 16 % to 40 % reduction in frictional contact surfaces. The analysis of experimental results showed that there is non‐linear relation between the frictional contact area and the pressing load. In addition, it is shown that despites high contact pressures and high temperatures the use of graphite as a lubricant between sliding surfaces can considerably reduce the pressing load.

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“…However, what is the influence of elastic rubber and its actual contact ratio? The contact ratio, α, is written as [24,25]…”

Section: Effect Of Contact Ratio At Soft Interfacementioning

confidence: 99%

Friction Performance of Rubber Sealing Disc Inside Pipe Robots for the Production of High-Paraffin Oil

Tan,

Luo,

et al. 2024

Lubricants

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The in-pipe robot is the most commonly used technique in offshore pipelines. The use of rubber sealing discs is important for in-pipe robots to ensure that the robots are moved by fluid pressures inside offshore pipelines. This paper focuses on the measuring and modeling of the wax–oil gel-breaking process at the soft frictional area between sealing discs and the pipe wall. In this study, a detailed characterization of the gel-scraping process and in situ probing portable microscopy are performed. Two contributions are made in this study. First, a direct observation of wax–oil deposition breaking is employed to detect the minute changes at the in-pipe robot. Second, we find that a simple function is possible to describe the relationship between the wax contents and dewaxing efficiency, in which the debris material removal ratio (DRR) is discussed. Thus, the gel deposition-breaking phenomena are quite different under the influence of rubber sealing discs. This result is further confirmed by the real contact ratio measurements. It is important to research the sealing disc further and apply it more in the petroleum industry, especially in in-pipe robots for deepwater pipeline systems.

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An experimental study on the relation between friction force and real contact area

Cited by 34 publications

References 35 publications

Insights into the Multiscale Lubrication Mechanism of Edible Phase Change Materials

Insights into the Multiscale Lubrication Mechanism of Edible Phase Change Materials

A novel equal channel angular pressing design to eliminate punch deflection and to reduce the pressing force

Friction Performance of Rubber Sealing Disc Inside Pipe Robots for the Production of High-Paraffin Oil

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