• Main projects in execution.
• Facilities.
• Members.

Main projects in execution

Granular materials: The study of the unique features of granular materials is a major goal for the next five years. From a practical view point, difficulties to achieve a good understanding of these materials relate to the absence of well adapted experimental techniques and the limited power of numerical methods. Experimental configurations to study granular flows inspired by the mining industry, such as hoppers flows, block caving and surface avalanches, will be developed as well as numerical calculations capable to describe realistic three dimensional configurations in problems such as particle size segregation and the granular flows induced by external forcing. New experimental tools, such as interferometric techniques, as well as theoretical modeling will be developed to characterize plastic flows in granular materials. Recent advances in CIMAT in the understanding of solitary wave dynamics will be brought to bear in the study of the force distribution and the propagation of mechanical excitation in consolidated granular materials.

New tools for the characterization of the mechanical properties of complex materials and membranes: The development of a variety of mechanical (especially acoustical) methods for the characterization of complex materials, including bioceramics, two phase systems, nanomembranes and filaments such as axons, is another major goal for the period.

The behavior of acoustic waves in complex materials will be studied using a variety of experimental as well as theoretical tools: Techniques developed at CIMAT allow for the reliable estimate of the sound velocity, and therefore of elastic properties, in samples whose thickness cannot be accurately determined; these techniques will be used to measure properties of soft materials such as biological tissues (human, animal and vegetal), gels and soft polymers. The collective behavior of complex fluids, such as suspensions or fluids filled with gas bubbles, and their response to acoustic forcing, will be studied experimentally as well as with recently developed mean-field theoretical modeling, with the aim of understanding the dynamics of self-organization or aggregation in systems where energy is continuously injected, as well as the effect of the interactions between objects and the structure of two-phase media on the effective macroscopic properties of such systems. The sound emitted by bubbles collapsing at the surface of a complex fluid will also be studied experimentally as well as theoretically, having in mind the possible development of a diagnostic of value in vulcanology. A general understanding will be sought on the role played by acoustic and solitary structures on the mass transport, and consequently on the dynamics, of a spinodal phase transition; model experiments will be developed to check the main theoretical predictions with an eye on possible applications to polymers and solid mixtures. The theoretical study started at CIMAT of the interaction of acoustic waves with dislocations will be continued and an experimental study will be started with the aim of developing nonintrusive tools for use in the study of plasticity.

Instrumentation developed at CIMAT has been used to study the elastic properties of a variety of natural bioceramics, such as eggshells, seashells, and spines. These studies will be continued, in conjuction with recently developed methods of speckle interferometry, that allow for the characterization of displacement and strain fields, and theoretical modeling. They will also be extended to include new polymeric materials.

Members

• Patricio Cordero, associate investigator.
• Fernando Lund, principal investigator.
• Enrique Tirapegui, associate investigator.

Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile. Av. Blanco Encalada 2008 piso zócalo, Santiago, Chile. Teléfono (56 2) 678 48 55