Statistical and Dynamical Properties of Spherical and Non-Spherical Granular Materials

Clark University, Worcester MA

Investigators

Abstract

Non-technical abstract: Experiments with high-speed imaging techniques will be conducted to understand the impact of particle shape and magnetization on the properties of granular matter. These studies are important because granular materials are ubiquitous constituents in industrial processes (e.g., food grain silos, fertilizers) and natural phenomena (e.g., mudslides), and yet no fundamental theory is currently available to describe them. We propose to test and develop mathematical model for granular matter over a wide range of parameters. Furthermore, grains come in all shapes and it is important to incorporate its impact into models that describe how different kinds of grains organize and flow. The proposed work will have significant impact on graduate student training. The grant will enhance research experience of undergraduate students in the laboratory, and the research will be also adapted into a modern course on mechanics. Local community will be exposed to the research via topical workshops, and by the researchers speaking at neighboring high schools to excite interests in the sciences. Technical abstract: The statistical and dynamical properties of spherical and non-spherical vibro-fluidized granular materials will be investigated with high-speed imaging techniques. The impact of particle shape will be the main focus and will be studied using vibrated rods, dimers, and polymers composed of linked bead chains. The impact of dissipation and anisotropic interactions on the self-assembly of novel structures and global dynamics will be probed. In thermal systems, long-range order is observed in oblate particles leading to nematic and smectic states which is said to simplify analysis. Whether interparticle friction in granular matter suppresses uniform exploration of phase space, as assumed by such approaches, is an open question. The effect of magnetization and long-range interaction on the self-assembly will be also studied, and compared with the dipolar hard sphere model developed for ferro-fluids. The extent to which equilibrium statistical physics and entropic considerations apply to dissipative granular systems will be investigated. Such experiments are interesting in the context of finding effective strategies for self-assembly in nano-particles as well. Besides developing fundamental knowledge on materials which need to be handled more efficiently in industry, the proposed work will directly support training of graduate students, enhance research experience of undergraduate students, impact development of a modern mechanics course, and impact the local community by engaging students in neighboring high schools via lectures.