Doctorado en Ciencia con mención en Física
Departamento de Física, Universidad de Santiago de Chile
Tesis : “Reología de un Sistema Granular Bidimensional: Caracterización de eventos locales por Fotoelasticidad”
Profesor Guía: Dr. Francisco Melo H.
The research focuses on studying the rheology of granular media in a two-dimensional system subjected to shear stress, by techniques of photoelasticity.
We study the behavior of the micro-structure of granular media, and the connection to the macroscopic behavior in the material. For the rheological characterization of the medium, we study the relaxation in quasi-static regime with constant load, and on the other hand, the evolution of the granular medium versus controlled-rate deformation, for small and high deformations.
In the quasi-static regime, was characterized the structure "microscopic" determined by the interaction between the grains, which manifests by the macroscopic relaxation. This regime is studied by Creep tests and macroscopic response of granular media. We hope determine the limit loads, and characteristic times for relaxation.
In the dynamic regime, the granular material is subjected to deformation with controlled rate, for the quantitative description of the accumulated deformation we use the Stress Tensor, and for the description of the anisotropy we use the Fabric Tensor. We expect to determine critical information about;
a) Information that can predict the onset of the flow of material.
b) The characteristics of the micro-structure that favor the flow of granular media, and
c) Characterize the local fluctuations through the contact forces between grains, and how they influence the fluctuations in the granular medium as a whole.
Is expected to obtain key information to describe, the transition between static and plastic deformations in granular materials.