Improved viscoplastic models in the flow of granular materials

ELASKAR, SERGIO; GODOY, LUIS

LATIN AMERICAN APPLIED RESEARCH

PLAPIQUI(UNS-CONICET)

Año: 2000 vol. 30 p. 201 - 211

0327-0793

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} h4 {mso-style-next:Normal; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; page-break-after:avoid; mso-outline-level:4; font-size:12.0pt; mso-bidi-font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-bidi-font-weight:normal;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Theoretical models are presented to represent the flow of granular materials stored in silos and hoppers by means of fluid flow formulation. The presentation follows previous work by Diez and Godoy (1992) using viscoplasticity, and refinement are introduced to improve the convergence of the solution and satisfaction of the constitutive equations. First, a model with constraints is developed in which the apparent viscosity has upper and lower boundaries to account for rigid behavior. A second model uses viscoplasticity with modified function of discontinuity and a weighting factor on selective terms of the apparent viscosity. The first model improve convergence but leads to unsatisfactory values compared with experimental results. The second model controls convergence by the weighting factor and shows good agreement with experiments.