PhD, Faculty of Engineering, University of the Witwatersrand, 1990

Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xiii, 122 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 100-106).

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 98-103).

Call number: LD2668 .T4 1978 W91 / Master of Science

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No description available.

A study of the constitutive equations of the flow of cohesionless granular materials at large rates of deformation and low stress levels is presented. The interstitial fluid effects are assumed negligible and the particles approximately incompressible. / Dimensional arguments and experimental observations suggest that two different regimes of flow may occur. At low rates of deformation, the Coulomb friction gives rise to stresses that are rate independent (of the plastic type). At large rates of deformation, momentum transfer arises from particles collisions and the resulting stresses become rate dependent (of the viscous type). A continuum model that includes both types of behaviour is proposed. The equilibrium part of the stress tensor satisfies the Mohr-Coulomb yield criterion and a non-coaxial flow rule. The viscous part is assumed to have a form corresponding to an isotropic Reiner-Rivlin fluid. / Experiments of simple shear flow flow in an annular shear cell were performed on several types of dry granular materials. The purpose of the tests was to obtain the information needed for the continuum description of the material behaviour. At lower solids concentrations and high shear rates where the inter-particle collisions are dominant, both shear and normal stresses were proportional to the square of the shear rate. At higher concentrations and lower shear rates, Coulomb friction between particles became increasingly important and the stresses were proportional to the shear rate raised to a power less than two. All tests showed a strong dependence upon solids concentration.

Thesis (M.S.)--University of North Texas, Dec., 2009. / Title from title page display. Includes bibliographical references.

Includes bibliographical references (p. 239-255).

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