Studies on granular materials. II. Apparatus for measuring the dynamic angle of internal and external friction of granular materials

Novosád, Jan

doi:10.1135/cccc19642697

Cited by 26 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For high deformation rates (2.1) tends to where 6,(v) is the dynamic friction angle which typically appears from experimental measurements to be fairly close to 6,. Annular-shear-cell tests using quartz particles and other geological materials have been performed to investigate rate effects by Novosad (1964), Bridgwater (1972), Savage & Sayed (1984), Hungr & Morgenstern (1984b), Hanes & Inman (1985) and by Buggisch and Stadler (Stadler & Buggisch 1985;Stadler 1986;Buggisch & Stadler 1986). These tests were performed by two quite different procedures.…”

Section: Discussion Of Major Assumptions 211 Experimental Evidence mentioning

confidence: 99%

“…To quote from the paper of Hanes & Inman (1985): 'The standard deviations of the stress ratios are approximately 10% of the mean, supporting the concept of a nearly constant stress ratio (over a range of shear rates and applied normal stresses) for a given material. ' An alternative type of test procedure (which might be regarded as a soil mechanics approach) has been used for example by Novosad (1964), Bridgwater (1972), Hungr & Morgenstern (19846) and Buggisch and Stadler (Stadler & Buggisch 1985;Stadler 1986 ; Buggisch & Stadler 1986). Typically they determined shear stress as a function of rotation rate for a constant applied normal stress.…”

Section: Discussion Of Major Assumptions 211 Experimental Evidence mentioning

confidence: 99%

See 1 more Smart Citation

The motion of a finite mass of granular material down a rough incline

1989

View full text Add to dashboard Cite

Rock, snow and ice masses are often dislodged on steep slopes of mountainous regions. The masses, which typically are in the form of innumerable discrete blocks or granules, initially accelerate down the slope until the angle of inclination of the bed approaches the horizontal and bed friction eventually brings them to rest. The present paper describes an initial investigation which considers the idealized problem of a finite mass of material released from rest on a rough inclined plane. The granular mass is treated as a frictional Coulomb-like continuum with a Coulomb-like basal friction law. Depth-averaged equations of motion are derived; they bear a superficial resemblance to the nonlinear shallow-water wave equations. Two similarity solutions are found for the motion. They both are of surprisingly simple analytical form and show a rather unanticipated behaviour. One has the form of a pile of granular material in the shape of a parabolic cap and the other has the form of anM-wave with vertical faces at the leading and trailing edges. The linear stability of the similarity solutions is studied. A restricted stability analysis, in which the spread is left unperturbed shows them to be stable, suggesting that mathematically both are possible asymptotic wave forms. Two numerical finite-difference schemes, one of Lagrangian, the other of Eulerian type, are presented. While the Eulerian technique is able to reproduce theM-wave similarity solution, it appears to give spurious results for more general initial conditions and the Lagrangian technique is best suited for the present problem. The numerical predictions are compared with laboratory experiments of Huber (1980) involving the motion of gravel released from rest on a rough inclined plane. Although in these experiments the continuum approximation breaks down at large times when the gravel layer is only a few particle diameters thick, the general features of the development of the gravel mass are well predicted by the numerical solutions.

show abstract

Section: Discussion Of Major Assumptions 211 Experimental Evidence mentioning

confidence: 99%

Section: Discussion Of Major Assumptions 211 Experimental Evidence mentioning

confidence: 99%

The motion of a finite mass of granular material down a rough incline

1989

View full text Add to dashboard Cite

show abstract

“…Hvorslev (1936Hvorslev ( , 1939 was the first to design an annular shear cell for soil testing. Low-strain-rate shear cells have been developed subsequently for the purpose of obtaining information for the design of bulk-solids-handling equipment by Novosad (1964), Carr & Walker (1967/68), Scarlett & Todd (1968, Scarlett et al (1969/70), Mandl, deJong & Maltha (1977) and Stephens & Bridgwater (1978a, b ) .…”

Section: Introductionmentioning

confidence: 99%

Stresses developed by dry cohesionless granular materials sheared in an annular shear cell

1984

View full text Add to dashboard Cite

Experimental results obtained during rapid shearing of several dry, coarse, granular materials in an annular shear cell are described. The main purpose of the tests was to obtain information that could be used to guide the theoretical development of constitutive equations suitable for the rapid flow of cohesionless bulk solids at low stress levels. The shear-cell apparatus consists of two concentric disk assemblies mounted on a fixed shaft. Granular material was contained in an annular trough in the bottom disk and capped by a lipped annular ring on the top disk. The bottom disk can be rotated at specified rates, while the top disk is loaded vertically and is restrained from rotating by a torque arm connected to a force transducer. The apparatus was thus designed to determine the shear and normal stresses as functions of solids volume fraction and shear rate.Tests were performed with spherical glass and polystyrene beads of nearly uniform diameters, spherical polystyrene beads having a bimodal size distribution and with angular particles of crushed walnut shells. The particles ranged from about ½ to 2 mm in size. At the lower concentrations and high shear rates the stresses are generated primarily by collisional transfer of momentum and energy. Under these conditions, both normal and shear stresses were found to be proportional to the particle density, and the squares of the shear rate and particle diameter. At higher concentrations and lower shear rates, dry friction between particles becomes increasingly important, and the stresses are proportional to the shear rate raised to a power less than two. All tests showed strong increases in stresses with increases in solids concentrations. The ratio of shear to normal stresses showed only a weak dependence upon shear rate, but it increased with decreasing concentration. At the very highest concentrations with narrow shear gaps, finite-particle-size effects became dominant and differences in stresses of as much as an order of magnitude were observed for the same shear rate and solids concentration.

show abstract

“…The technique has been used to design handling procedures for a variety of powders Allen, 1966;Kott and Kramer, 1966) and Eaves and Jones (1970) measured lactose and sodium chloride in a shear cell. Cells have been developed in which the powder shears in an annulus and, thus, the bed is consolidated and sheared in a continuous operation (Novosad, 1964;Walker, 1967). Scarlett and Todd (1968) modified the design so as to form a split-ring annular cell which eliminated wall friction.…”

Section: B Cohesion and Tensile Strengthmentioning

confidence: 99%

Recent Advances in Pharmaceutical Rheology

Barry

1970

Journal of Texture Studies

View full text Add to dashboard Cite

Significant advances in rheology of pharmaceutical and allied materials since 1965 are covered in a review of 292 references. The subject matter is divided into considerations of powders, suspensions and suspending agents, semi-solids (creams and ointments), emulsions, suppositories and pessaries, foam aerosols and a general section. Material related to tablets, biorheology, and surface and interfacial films is not considered.

show abstract

Studies on granular materials. II. Apparatus for measuring the dynamic angle of internal and external friction of granular materials

Cited by 26 publications

References 0 publications

The motion of a finite mass of granular material down a rough incline

The motion of a finite mass of granular material down a rough incline

Stresses developed by dry cohesionless granular materials sheared in an annular shear cell

Recent Advances in Pharmaceutical Rheology

Contact Info

Product

Resources

About