Doctorado en Ciencias con mención en Física
Universidad de Santiago de Chile
Tesis: "Propagación y emisión de sonido en materiales granulares: Inestabilidades bajo perturbaciones sónicas"
Dr. Francisco Melo
En colaboración con Dr. Belfor Galáz
A granular material is composed of macroscopic particles that interact via dissipative contact forces. Ultrasound can be used as a powerful tool that allows us to know the mechanical properties and how they change when we submit the material to some type of mechanical test such as a triaxial test or a creep test. Two regimes can be identified for ultrasound propagation in granular materials: short wavelength and long wavelength with respect to the size of the particles that compose the system. The first helps us to know average properties of granular material such as stiffness and the second gives information about the structure of the network of contacts in the system. For example, the global correlation coefficient of two scattering waves tell us whether there are differences between the networks.
On the other hand, the ultrasound also interacts with the system by modifying some mechanical properties, for example in the figure, we see that ultrasound accelerates the fluidization of the system, this phenomenon is known as acoustic fluidization.