Dynamic inter-particle friction of crushed limestone surfaces

Senetakis, Kostas; Sandeep, C.S.; Todisco, Maria Cristina

doi:10.1016/j.triboint.2017.02.036

Cited by 30 publications

(21 citation statements)

References 23 publications

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“…Senetakis et al [6] reported a reduction of the surface roughness of the order of 20% to 60%, but this reduction may have been the coupled result of the application of the normal load and the shearing test. Similar observations were reported by Senetakis et al [7] testing crushed limestone grains in their recent study. It is possible that this reduction of the surface roughness may have resulted in slightly different responses between the first and second cycle of shearing for the test at F N = 2 N. This is because the first shearing showed a peak state which was less apparent during the successive cycles, and that after the first cycle, the inter-particle friction dropped but without further notable reduction for the third and fourth shearing test.…”

Section: Tangential Load-displacement and Friction For The Lbs Grainssupporting

confidence: 92%

“…This system works in three perpendicular directions, allowing two grains of sand size to be in contact under a controlled normal load and one grain is sheared over the surface of the other grain, following relatively small shearing paths of the order of about 50 to 300 microns. Typically, the normal (vertical) load is applied in a force-controlled manner and the shearing in the tangential to the contact direction is applied through a force-or displacement-controlled type [5][6][7]10,11]. Typical plots of the normal load (FN) against the horizontal (sliding) displacement during micromechanical tests are given in Figure 4.…”

Section: Apparatus and Experimental Methods For The Micromechanical Tmentioning

confidence: 99%

“…Note that the grains are set prior to the shearing test, with an apex-to-apex type of contact. This configuration has allowed the systematic study of grain contact stiffness [5][6][7]10,11]. Stiffness could not be captured, for example, with the previous design by Cavarretta et al [4].…”

Section: Apparatus and Experimental Methods For The Micromechanical Tmentioning

confidence: 99%

“…From the first works published in 1960s and 1970s, for example by Horn and Deere [1] or Procter and Barton [2], to recent studies by Cole et al [3], Cavarretta et al [4], Senetakis et al [5][6][7] or Nardelli et al [8] some discrepancies with respect to the measured friction at the interface of geological materials have been noticed. Previous works had a particular focus on the development of laboratory apparatus quantifying the frictional response at the interface of geological materials, for example the studies by Cavarretta [4] or Yang et al [9].…”

Section: Introductionmentioning

confidence: 98%

“…Previous works had a particular focus on the development of laboratory apparatus quantifying the frictional response at the interface of geological materials, for example the studies by Cavarretta [4] or Yang et al [9]. However, the inter-particle stiffness could not be captured in laboratory tests until the recent works by Cole et al [3] and Senetakis et al [6,7]. This might be because of limitations of the capabilities of those laboratory systems to quantify micro-quantities at the contacts of grains which would require extremely high resolution of forces and displacements on the onset of about half a micron of shearing path.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Exploring the Micromechanical Sliding Behavior of Typical Quartz Grains and Completely Decomposed Volcanic Granules Subjected to Repeating Shearing

Sandeep

Senetakis

2017

Energies

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Abstract:The micromechanical behavior at grain contacts subjected to tangential and normal forces is of major importance in geotechnical engineering research and practice. The development of the discrete element method (DEM) over the past three decades necessitated a more systematic study on the experimental grain contact behavior of real soil grains as DEM simulations use as input tangential and normal load-displacement relationships at grain contacts. In this study, experimental results conducted at the City University of Hong Kong are presented exploring the tangential load-displacement behavior of geological materials. The focus of the study is to explore the possible effect of repeating the shearing test to the same grains on the inter-particle coefficient of friction accounting for the level of the applied normal load. Additionally, the study reports on the frictional behavior of different geological materials including quartz sand grains, denoted as Leighton Buzzard sand (LBS) in the study and completely decomposed volcanic granules denoted as CDV. Quartz grains may find applications as proppant in petroleum engineering, whilst the CDV granules consisted of a material taken from a recent landslide in Hong Kong, whose applications are related to debris flow. Through the micromechanical sliding experiments, the inter-particle coefficient of friction was quantified following shearing paths of about 60 to 200 microns. While at the smallest vertical load of 1 N, there was not observed a notable effect of the repeating shearing for the LBS grains, it was noticed that for small to medium vertical loads, between 2 and 5 N, the repeating shearing reduced the friction at the contacts of the LBS grains. This trend was clear between the first and second shearing, but additional cycles did not further alter the frictional response. However, at greater vertical loads, between 7 and 10 N, the results showed a continuous increase in the dynamic inter-particle friction for the LBS grains with repeating shearing. It was also noticed that at 7 and 10 N of vertical load, there was absence of a peak state in the tangential force-displacement plot, whereas a peak state was observed at smaller loads particularly for the first shearing cycle. These observations might be explained by the possible plowing effects at greater vertical loads which resulted in an increase of the inter-particle coefficient of friction when the shearing test was repeated. For the CDV granules, only the first shearing cycle gave a peak state and, in general, the effect of repeating the shearing was small but with an increase of the inter-particle friction from the first to the second cycle. Overall, during the repeating shearing the LBS grains had a dynamic inter-particle coefficient of friction that ranged between about 0.18 and 0.38, but the CDV granules exhibited much greater friction with values that corresponded to the steady state sliding that ranged between 0.54 and 0.66 . The observed trends in the study might be due to mechanisms that take place...

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Section: Tangential Load-displacement and Friction For The Lbs Grainssupporting

confidence: 92%

Section: Apparatus and Experimental Methods For The Micromechanical Tmentioning

confidence: 99%

Section: Apparatus and Experimental Methods For The Micromechanical Tmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Exploring the Micromechanical Sliding Behavior of Typical Quartz Grains and Completely Decomposed Volcanic Granules Subjected to Repeating Shearing

Sandeep

Senetakis

2017

Energies

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Optimization of PTFE/Cu/Al₂O₃ filled PMMA based composites on tribological properties using Taguchi design method

Zhang

Chen

et al. 2018

J of Applied Polymer Sci

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The filling combination of polytetrafluoroethylene (PTFE)/Cu/Al2O3 filled poly(methyl methacrylate) (PMMA) based composites aiming at low friction and wear is optimized based on L9(34) by Taguchi method. The worn morphologies of PMMA based composites are analyzed by scanning electron microscopy (SEM). The PTFE transfer film and the wear debris on the steel ball surface are analyzed by SEM and X‐ray spectroscopy. It is observed that the friction and wear of PMMA can be obviously decreased by filling with PTFE, Cu, and Al2O3. PTFE has the most significant but Cu has the negligibly smallest contribution on both the friction coefficient and the wear rate. The lower friction coefficient (<0.2) appears by the combination of the mass ratio of PTFE larger than about 4.5% and the mass ratio of Al2O3 lower than ∼7.5%. The lower wear rate (<5 × 10−5 mm3/Nm) appears by the combination of the mass ratio of PTFE larger than about 5% and the mass ratio of Al2O3 lower than ∼8%, but it does not include that PTFE is greater than about 8.5% and Al2O3 is less than about 1.5%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46705.

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Simulations of realistic granular soils in oedometer tests using physics engine

Zheng

2020

Num Anal Meth Geomechanics

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Summary Discrete element method (DEM) has become a preeminent numerical tool for investigating the mechanical behavior of granular soils. However, traditional DEM uses sphere clusters to approximate realistic particles, which is computationally demanding when simulating many particles. This paper demonstrates the potential of using a physics engine technique to simulate realistic particles. The physics engines are originally developed for video games for simulating physical and mechanical processes that occur in the real world to produce realistic game experiences. The simulation accuracy and efficiency of physics engines have been significantly improved in the last two decades allowing them to be used as a scientific tool in many disciplines. This paper introduces modeling methodologies of physics engine including realistic particle representation and the contact model. Then, oedometer tests are simulated using realistic particles scanned by X‐ray computed tomography (X‐ray CT). The simulation results agree well with experimental results. This paper demonstrates that physics engines can output contact parameters for geotechnical analysis and force chains for visualization.

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Dynamic inter-particle friction of crushed limestone surfaces

Cited by 30 publications

References 23 publications

Exploring the Micromechanical Sliding Behavior of Typical Quartz Grains and Completely Decomposed Volcanic Granules Subjected to Repeating Shearing

Exploring the Micromechanical Sliding Behavior of Typical Quartz Grains and Completely Decomposed Volcanic Granules Subjected to Repeating Shearing

Optimization of PTFE/Cu/Al₂O₃ filled PMMA based composites on tribological properties using Taguchi design method

Simulations of realistic granular soils in oedometer tests using physics engine

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Dynamic inter-particle friction of crushed limestone surfaces

Cited by 30 publications

References 23 publications

Exploring the Micromechanical Sliding Behavior of Typical Quartz Grains and Completely Decomposed Volcanic Granules Subjected to Repeating Shearing

Exploring the Micromechanical Sliding Behavior of Typical Quartz Grains and Completely Decomposed Volcanic Granules Subjected to Repeating Shearing

Optimization of PTFE/Cu/Al2O3 filled PMMA based composites on tribological properties using Taguchi design method

Simulations of realistic granular soils in oedometer tests using physics engine

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Product

Resources

About

Optimization of PTFE/Cu/Al₂O₃ filled PMMA based composites on tribological properties using Taguchi design method