Events Calendar

Modeling and Simulation of Multiphysical Processes in Particulate Media

Speaker: Dr. Tarek I. Zohdi,
Professor and Vice Chair for Instruction, The University of California, Berkeley Department of
Mechanical EngineeringABSTRACT: Ideally, in an attempt to reduce laboratory costs, one would like to make predictions of complex solid and fluid particulate material behavior by numerical simulations, with the primary goal being to minimize time-consuming trial and error experiments. A central objective of this presentation is to provide basic models and efficient numerical solution strategies for the direct simulation of complex particulate media that can be achieved within a relatively standard computing environment. Key corresponding laboratory experiments are also discussed. The topics to be touched upon are:(1) Electromagnetic Composites,
(2) Computational Bio-electromagnetics,
(3) Environmental Degradation of Composite Materials,
(4) Structural Fabric,
(5) Complex Particulate Flows and
(6) Generalizations to Modeling and Design of Collective Behavior.CONTEXT: Recently, several applications, primarily driven by micro-technology,have emerged where the use of solid, fluid and fabric materials with tailored mechanical, thermal and electromagnetic properties are necessary for a successful overall design. The "tailored" properties are achieved by combining an easily moldable base matrix with particles having material properties that are chosen to deliver overall macroscale (desired) effective properties. In many cases, the analysis of such materials requires the simulation of the strongly coupled, macroscopic and microscopic, mechanical, thermal and electromagnetic response,in order to identify possible failure at``hot spots'' within the microstructure. One of the key components in such composite systems are the microscale particulates, and their processing.External electromagnetic fields can be utilized to manipulate and control particulate flows during processing in order to achieve results that are not possible by purely mechanical means alone. Generally, industrial applications where this is important include electrostatic copiers, inkjet printers, powder coating machines, aerosol design, etc. For example, several industrial processes, such as Chemical Mechanical Planarization (CMP), involve using small-scale chemically-reacting particulates to ablate rough small-scale surfaces flat.These processes have become important for the success of many micro- and
nano- technologies. It is estimated that over 50 percent (by weight) of the materials used in high-end technology start out as particles or granulated material. Below a certain particle length-scale, approximately one millimeter, the dynamics of particles can be strongly affected inter-particle near-field forces, as well as external electromagnetic fields. During processing, whether intended or not, particulate agglomeration can occur.The dynamics of those clusters in the presence of an electromagnetic field are of high interest because they may lead to poor spray quality and inconsistent fabrication results, for example, of composite materials. Therefore, neglecting such near-field effects in an analysis can lead to a significant miscalculation of the characteristics of such flows. Thus, an issue of overriding importance to the successful characterization of such complex materials is the development of models and reliable computational techniques to simulate the response of composite particulate continua, as well as the dynamics and multiphysics of multibody particulate systems involving near-field interaction and contact simultaneously.

Location: Kaprielian Hall (KAP) - 209

Audiences: Everyone Is Invited

Contact: Evangeline Reyes