A new interparticle friction apparatus for granular materials

2011 ◽  
Vol 48 (12) ◽  
pp. 1829-1840 ◽  
Author(s):  
I. Cavarretta ◽  
I. Rocchi ◽  
M.R. Coop
Keyword(s):  
Granular Materials ◽  
Spherical Particle ◽  
Quartz Sand ◽  
Ball Bearings ◽  
Large Displacements ◽  
Simple Design ◽  
Stick Slip ◽  
New Apparatus ◽  
Sand Particles ◽  
Interparticle Friction

A new apparatus is described that measures interparticle friction between sand-sized grains over relatively large displacements and also under immersion in a fluid. Its relatively simple design allows the key calibrations to be checked by statics. An analysis of the geometry of simple spherical particle contacts and the forces at those contacts revealed that there are strict constraints on the permissible stiffness of the interparticle friction apparatus to avoid stick–slip behaviour. Tests on ball bearings gave highly repeatable data, while others on glass ballotini revealed a significant effect of ambient humidity on the data obtained. The interparticle friction was found to increase with the roughness of the ballotini. Immersion in water increased the interparticle friction slightly for both the ballotini and quartz sand particles, while immersion in oil reduced the friction considerably for the quartz sand, especially at higher contact force levels.

scholarly journals On unsteady flows of pore pressure-activated granular materials

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Anna Abbatiello ◽  
Miroslav Bulíček ◽  
Tomáš Los ◽  
Josef Málek ◽  
Ondřej Souček
Keyword(s):  
Granular Materials ◽  
Plastic Material ◽  
Pore Space ◽  
Nonlinear Partial Differential Equations ◽  
Large Data ◽  
Existence Theory ◽  
Solid Matrix ◽  
Lithostatic Pressure ◽  
Generalized Newtonian Fluid ◽  
Stick Slip

AbstractWe investigate mathematical properties of the system of nonlinear partial differential equations that describe, under certain simplifying assumptions, evolutionary processes in water-saturated granular materials. The unconsolidated solid matrix behaves as an ideal plastic material before the activation takes place and then it starts to flow as a Newtonian or a generalized Newtonian fluid. The plastic yield stress is non-constant and depends on the difference between the given lithostatic pressure and the pressure of the fluid in a pore space. We study unsteady three-dimensional flows in an impermeable container, subject to stick-slip boundary conditions. Under realistic assumptions on the data, we establish long-time and large-data existence theory.

Fabrication of recyclable superhydrophobic materials with self-cleaning and mechanically durable properties on various substrates by quartz sand and polyvinylchloride

RSC Advances ◽  
2016 ◽  
Vol 6 (82) ◽  
pp. 79238-79244 ◽  
Author(s):  
Mengnan Qu ◽  
Shanshan Liu ◽  
Jinmei He ◽  
Juan Feng ◽  
Yali Yao ◽  
...  
Keyword(s):  
Quartz Sand ◽  
Sand Particles ◽  
Self Cleaning

The recyclable superhydrophobic materials are successfully prepared by employing surface-functionalized quartz sand particles embedded into polyvinylchloride.

scholarly journals Particles fluidized bed receiver/reactor tests with quartz sand particles using a 100-kWth beam-down solar concentrating system at Miyazaki

2017 ◽  
Author(s):  
Tatsuya Kodama ◽  
Nobuyuki Gokon ◽  
Hyun Seok Cho ◽  
Koji Matsubara ◽  
Hiroshi Kaneko ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Quartz Sand ◽  
Sand Particles

scholarly journals The Analysis of Erosive Wear Resistance of WC-Co Carbides Obtained by Spark Plasma Sintering Method

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7326
Author(s):  
Joanna Wachowicz ◽  
Tomasz Dembiczak ◽  
Grzegorz Stradomski ◽  
Zbigniew Bałaga ◽  
Joanna Jasińska ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Quartz Sand ◽  
Metal Cutting ◽  
Oriented Strand Board ◽  
Cutting Tools ◽  
Erosive Wear ◽  
Plasma Sintering ◽  
Erosion Models ◽  
Spark Plasma ◽  
Sand Particles

WC-Co (tungsten carbide-cobalt) composites are widely used in industry, wear-resistant parts, and cutting tools. As successful tool materials, WC-Co carbides are widely applied in metal cutting, wear applications, chipless forming, stoneworking, wood, and plastic working. These materials are exposed to severe solid particle erosion by sand particles, such as in the wood industry. During the production of furniture with HDF (High Density Fibreboard), MDF (Medium Density Fibreboard), or OSB (Oriented Strand Board), there are observed problems with tool erosion. Contamination, mainly of the HDF by sand, is quite often, which is why all tools used for the machining of such materials are exposed to erosion by sand particles. Although many studies have been performed on the erosion of various metals, and erosion models exist to predict their erosion behavior, the issue is still relevant. The aim of the study was to determine the effect of grain size (submicron, ultrafine) and the manufacturing technology (SPS—Spark Plasma Sintering, conventional) used on the erosive properties of WC-Co sintered carbides. Sinters produced by the SPS method with different sizes of WC grains and commercial samples were used for the tests. Ten two-hour cycles were carried out under medium conditions of quartz sand and quartz sand with 10% SiC added. Used samples were characterised using scanning electron microscopy (SEM) and roughness was determined. Furthermore, erosion studies allowed individuating a wear mechanism as well as the possibility to foresee cutting performance in prospective application.

Numerical simulations of a stick-slip spherical particle in Poiseuille flow

2019 ◽  
Vol 31 (8) ◽  
pp. 083603 ◽  
Author(s):  
Marco Trofa ◽  
Gaetano D’Avino ◽  
Pier Luca Maffettone
Keyword(s):  
Numerical Simulations ◽  
Spherical Particle ◽  
Poiseuille Flow ◽  
Stick Slip

INFLUENCE OF THE IMPACT ANGLE OF A SOLID PARTICLE JET ON THE EROSION WEAR OF 38GSA AND HARDOX 500 STEEL

Tribologia ◽  
2017 ◽  
Vol 273 (3) ◽  
pp. 85-90 ◽  
Author(s):  
Bazyli KRUPICZ ◽  
Wojciech TARASIUK ◽  
Jerzy NAPIÓRKOWSKI ◽  
Krzysztof LIGIER
Keyword(s):  
Mechanical Properties ◽  
Kinetic Energy ◽  
Solid Particle ◽  
Quartz Sand ◽  
Impact Angle ◽  
Erosion Wear ◽  
Sand Particles ◽  
Work Of Deformation ◽  
The Impact

The paper investigated the influence of the impact angle of a solid particle jet on the erosion wear of 38GSA and Hardox 500 steel. The basis of the analysis was the assumption of the existence of a correlation between mechanical properties of the material, represented by the work of deformation (P) determined from the stressstrain diagram (U). The impact angle of quartz sand particles (30, 60, and 90 °) was considered through the separation of kinetic energy of particles impacting the eroded surface perpendicularly and tangentially.

scholarly journals Practical Limits to the Performance of Magnetic Bearings: Peak Force, Slew Rate, and Displacement Sensitivity

1989 ◽  
Vol 111 (2) ◽  
pp. 331-336 ◽  
Author(s):  
E. Maslen ◽  
P. Hermann ◽  
M. Scott ◽  
R. R. Humphris
Keyword(s):  
Magnetic Bearing ◽  
Peak Force ◽  
Magnetic Bearings ◽  
Design Tools ◽  
Large Displacements ◽  
Simple Design ◽  
Slew Rate ◽  
Performance Limits ◽  
Displacement Sensitivity

Magnetic bearings are subject to performance limits which are quite different from those of conventional bearings. These are due in part to the inherent nonlinearity of the device and in part to its electrical nature. Three important nonideal behaviors are presented: peak force capacity, force slew rate limitation, and sensitivity to rotor motion at large displacements. The problem of identifying the dynamic requirements of a magnetic bearing when used to support a known structure subject to known loads is discussed in the context of these limits. Several simple design tools result from this investigation.

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