The angle of internal friction as a measure of work loss in granular material flow

2013 ◽  
Vol 233 ◽  
pp. 347-353 ◽  
Author(s):  
Jiri Zegzulka
Keyword(s):  
Internal Friction ◽  
Granular Material ◽  
Material Flow ◽  
Work Loss ◽  
Angle Of Internal Friction

Simulating a direct shear box test by DEM

2006 ◽  
Vol 43 (2) ◽  
pp. 155-168 ◽  
Author(s):  
S H Liu
Keyword(s):  
Contact Angle ◽  
Internal Friction ◽  
Granular Material ◽  
Distinct Element ◽  
Contact Forces ◽  
Interparticle Contact ◽  
Direct Shear ◽  
Angle Of Internal Friction ◽  
Shear Box ◽  
Direct Shear Box Test

Distinct element simulation was performed for direct shear box (DSB) tests on a dense and a loose two-dimensional (2D) sample of 3259 cylinders. Special attention was devoted to the effect that the frictional force between the inside surface of the upper shear box and the sample had on the measured shear strength in the DSB test. Some ways of minimizing this interface frictional force were introduced in the paper. Given that the deformation approximates simple shear within the deforming zone across the sample centre (referred to as the shear zone), a method was proposed to evaluate the overall strains in the DSB test. The numerically simulated data were used to interpret, on a microscopic scale, the angle of internal friction and a 2D stress–dilatancy equation for the mobilized plane in granular material. It was found that the angle of internal friction in granular material is not directly related to the interparticle friction angle (ϕµ). Instead, it relates to the average interparticle contact angle ([Formula: see text]) on the mobilized plane and the ratio k/f0, representing the degree of the probability distribution of the interparticle contact forces that is biased toward the positive zone of the contact angle θ (along the shear direction), where k is the slope of the linear distribution of the average interparticle contact forces against the interparticle contact angle; and f0 is the average interparticle contact force.Key words: angle of internal friction, direct shear box test, distinct element method, friction, granular material, stress–dilatancy.

scholarly journals Shear strength characteristics of Jerash expansive soil

2021 ◽  
Vol 3 (2) ◽  
pp. 74-80
Author(s):  
Talal Masoud
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Water Content ◽  
Direct Shear Test ◽  
Shear Test ◽  
Expansive Soil ◽  
Content Increase ◽  
Direct Shear ◽  
Initial Water ◽  
Angle Of Internal Friction

The results of the direct shear test on Jerash expansive soil show the effect of the initial water content on the cohesion (c) and on the angel of internal friction ( ) [shear strength parameters].it show that, as the initial water increase, the cohesion (c) of Jerash expansive soil also increase up to the shrinkage limit, after that increase of water even small amount, decrease the cohesion of the soil. On the other hand, the results of direct shear test show also  that as the water content increase, the angle of internal friction ( )remain unchanged up to shrinkage limit , any increase of water cause a large decrease on the angle of internal friction of Jerash expansive soil.

scholarly journals Multivariate Analyses of Selected Mechanical Properties of Dry Bean Grain

2015 ◽  
Vol 29 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Hakan Kibar
Keyword(s):  
Principal Component Analysis ◽  
Internal Friction ◽  
Lateral Pressure ◽  
Bulk Material ◽  
Poisson Ratio ◽  
Pressure Ratio ◽  
Principal Component ◽  
Component Analysis ◽  
Dry Bean ◽  
Angle Of Internal Friction

Abstract The direct shear test are widely used to measure the bulk material properties for economical design of bulk handling equipment and to estimate wall pressure inside storage structures, namely their bulk density, the angle of internal friction, shear strength, Poisson ratio, and lateral pressure ratios are required. Tests were conducted at thirty six different shear speeds (between 0.30-1.00 mm min-1) and three different normal stresses were applied (60, 120 and 180 kPa). The angle of internal friction, Poisson ratio, and lateral pressure ratios demonstrated fluctuations depending on the shear speeds. The results of the principal component analysis indicated that the first three principal components accounted for 97.40% of the total variability among the thirty six different shear speeds for all the traits investigated. The first principal component was the most important. In the result of principal component analysis, the shear speeds were divided into seven clusters. The pressures were decreased and increased with the change of the angle of internal friction and the lateral pressure ratio. The data obtained from the study will be useful in the structural design of dry bean bins to calculate loads on bins from the stored material and grain handling equipment.

Elimination of Vibrations in an Ore Unloading Bin

1974 ◽  
Vol 96 (3) ◽  
pp. 761-764 ◽  
Author(s):  
M. L. Wei ◽  
J. R. Johanson
Keyword(s):  
Granular Material ◽  
Flow Control ◽  
Material Flow ◽  
Natural Frequencies ◽  
Flow Patterns ◽  
Corrective Measures

Problems of undesirable vibrations in an ore unloading structure are described. Earlier unsuccessful attempts to eliminate vibrations by changing allegedly exciting frequencies mechanically and by increasing natural frequencies structurally are cited. Scientific evaluations of granular material flow patterns in the bin are presented, which identify possible causes of and methods to alleviate the vibrations. Finally, the corrective measures in flow control taken to eliminate vibrations are illustrated.

scholarly journals Flow and Thermal Properties of Stevia Powder

2018 ◽  
Vol 21 (2) ◽  
pp. 51-55 ◽  
Author(s):  
Ajit K. Mahapatra ◽  
Agnes J. Kapsoiyo ◽  
Sierra C. Birmingham ◽  
Daniel Ekefre ◽  
Bipul K. Biswas
Keyword(s):  
Thermal Properties ◽  
Internal Friction ◽  
Polynomial Regression ◽  
Stevia Rebaudiana ◽  
Calorific Value ◽  
Flow Index ◽  
Published Data ◽  
Mean Flow ◽  
Angle Of Internal Friction ◽  
The Mean

Abstract Stevia (Stevia rebaudiana Bertoni) has recently received a lot of attention as a sweetener due to its taste and low calorific value. Flow and thermal properties of foods play a significant role in the quantitative analysis of unit operations in the food industry. However, there are no published data available on flow and thermal properties of stevia powder. Powder Flow Tester and KD2 Pro Thermal Properties Analyzer were used to determine the flow and thermal properties of stevia powder, respectively, at different moisture contents (4.96%, 9.68%, 13.99%, 20.08%, and 25.79%, w.b.). Mean angle of internal friction of stevia powder ranged from 41.13° to 46.3°. The mean effective angle of internal friction ranged from 47.8° to 52.5° and the mean flow index ranged from 0.27 to 0.48. Mean thermal conductivity of stevia powder ranged from 0.091 W·m-2·K-1 to 0.115 W·m-2·K-1. Mean thermal diffusivity ranged from 0.103 mm2·s-1 to 0.121 mm2·s-1 and mean volumetric specific heat ranged from 0.865 MJ·m-3·K-1 to 1.019 MJ·m-3·K-1. Polynomial regression models were developed to predict flow and thermal properties of stevia powder using moisture content of stevia powder.

scholarly journals A Comparative Analysis of the Flow Properties between Two Alumina-Based Dry Powders

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Milene Minniti de Campos ◽  
Maria do Carmo Ferreira
Keyword(s):  
Internal Friction ◽  
Moisture Content ◽  
Ceramic Powder ◽  
Morphological Characteristics ◽  
Angle Of Repose ◽  
Wall Friction ◽  
Flow Index ◽  
Alumina Powder ◽  
Flow Properties ◽  
Angle Of Internal Friction

We measured and compared the flow properties of two alumina-based powders. The alumina powder (AP) is irregularly shaped and has a smooth surface and moisture content of 0.16% (d.b.), and the ceramic powder (CP), obtained after atomization in a spray dryer, is spherical and has a rough surface and moisture content of 1.07%. We measured the Hausner ratio (HR), the static angle of repose (AoR), the flow index (FI), the angle of internal friction, and the wall's friction angle. The properties measured using aerated techniques (AoR and HR) demonstrated that AP presents true cohesiveness (and therefore a difficult flow), while CP presents some cohesiveness and its flow might be classified as half way between difficult and easy flow. Their FI values, which were obtained using a nonaerated technique, enable us to classify the alumina as cohesive and the ceramic powder as an easy-flow powder. The large mean diameter and morphological characteristics of CP reduce interparticle forces and improve flowability, in spite of the higher moisture content of their granules. The angles of internal friction and of wall friction were not significantly different when comparing the two powders.

scholarly journals Response of granular-material flow to abrupt change of surface-shear force

1996 ◽  
Vol 40 ◽  
pp. 1045-1050
Author(s):  
Hitoshi GOTOH ◽  
Tetsuo SAKAI ◽  
Yasuharu TOYOTA ◽  
Atsushi SAKAI
Keyword(s):  
Granular Material ◽  
Material Flow ◽  
Shear Force ◽  
Abrupt Change ◽  
Surface Shear

Soil Mechanics as it Affects Vehicle Performance

1966 ◽  
Vol 3 (4) ◽  
pp. 204-216
Author(s):  
Nyal E Wilson ◽  
Henry R Krzywicki
Keyword(s):  
Internal Friction ◽  
Slope Stability ◽  
Graphical Method ◽  
Soil Mechanics ◽  
Principal Stresses ◽  
Vehicle Performance ◽  
X Ray ◽  
Stability Problems ◽  
Angle Of Internal Friction ◽  
Rigid Model

A fundamental approach to mobility by studying deformations and stresses in a soil as a wheel moves is described. A driven rigid model wheel was constructed to run over a sample of amorphous granular peat. Metal markers were placed throughout the peat and records of their movements, using an X-ray technique, were obtained as the wheel travelled over the peat. The markers moved in cardioids (heart shapes). The marker movement for any location within the sample was obtained from relationships which existed between the movement of the markers and the positions of the wheel.The trajectories of the principal stresses were determined from the deformations by a graphical method. Using an assumption regarding the angle of internal friction for this peat, the surfaces of maximum shear were obtained. The surfaces of maximum shear resembled the configurations associated with slope stability problems in soil mechanics.

scholarly journals Models for evaluating craters morphology, relation of indentation hardness and uniaxial compressive strength via a flat-end indenter

2018 ◽  
Vol 10 (1) ◽  
pp. 289-296 ◽  
Author(s):  
Ligang Zhang ◽  
Xiao Fei Fu ◽  
G. R. Liu ◽  
Shi Bin Li ◽  
Wei Li ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Internal Friction ◽  
Uniaxial Compressive Strength ◽  
Poisson’S Ratio ◽  
Failure Process ◽  
Apex Angle ◽  
Poisson's Ratio ◽  
Percentage Error ◽  
Indentation Hardness ◽  
Angle Of Internal Friction

AbstractIn this work, the intensive theoretical study and laboratory tests are conducted to evaluate the craters morphology via the flat-ended indenter test, relationship of indentation hardness (HRI) and uniaxial compressive strength (UCS). Based on the stress distribution, failure process and Mohr–Coulomb failure criterion, the mathematical mechanical models are presented to express the formation conditions of “pulverized zone” and “volume break”. Moreover, a set of equations relating the depth and apex angle of craters, the ratio of indentation hardness and uniaxial compressive strength, the angle of internal friction and Poisson’s ratio are obtained. The depth, apex angle of craters and ratio of indentation hardness and uniaxial compressive strength are all affected by the angle of internal friction and Poisson’s ratio. The proposed models are also verified by experiments of rock samples which are cored from Da Qing oilfield, the percentage error between the test and calculated results for depth, apex angle of craters and the ratio of HRI and UCS are mainly in the range of –1.41%–8.92%, –5.91%–3.94% and –8.22%–13.22% respectively for siltstone, volcanic tuff, volcanic breccia, shale, sand stone and glutenite except mudstone, which demonstrates that our proposed models are robust and effective for brittle rock.

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