Multifunctional Materials: A New Horizon in Engineering Science

Speaker:Prof. Sia Nemat-Nasser
Department of Mechanical and Aerospace Engineering
Center of Excellence for Advanced Materials
9500 Gilman Drive, La Jolla, CA 92093-0416
University of California San DiegoAbstract:Multifunctional materials and structures are systems designed and manufactured to possess one or more integrated functionality, in addition to their required mechanical and load-bearing attributes. Essentially all biological systems have integrated multifunctional capabilities. Few traditional structural systems are multifunctional. Development of multifunctional materials and hence structures requires a multidisciplinary approach that has been the hallmark of Engineering Science. Recent years have witnessed an avalanche of governmental initiative for research in multifunctional materials and structures. In this talk, I will review a class of multifunctional lightweight composites which have tuned electromagnetic (EM) signature management and sensing, self-crack-healing, thermal management, as well as being structurally strong and tough. The EM functionality is produced by integrating into the composite's fabric minute amounts of conductors of optimal configuration, which leads to composites with desired electric permittivity and magnetic permeability. For example, a solid composite of this kind can be tuned to have an index of refraction of 1 over a desired frequency range, rendering the solid fully EM-transparent in that frequency range. The wire conductors are integrated into the composite's fiber reinforcing braids that also include Kevlar, glass, or other desired strengthening constituents. For the matrix material, we are considering a newly developed polymer in which micro-cracks can heal, reversibly and at the molecular level, through the application of moderate heat and pressure. The conductive wires embedded in the composites can be used as resistive elements to heat the material, as sensors to detect internal damage, and as electrical conductors to tune the electromagnetic properties of the system. The next step is to add information-based properties into such multifunctional composites, mimicking nature's approach to local and global information acquisition, processing, and communication. Time permitting, the lecture will also explore some of the interwoven challenges that must be successfully met in order to create intelligently-sensing composite materials that are aware of their environmental and internal changes; and can selectively acquire, process, and store or communicate information locally and globally. Multifunctional composites of this kind enhance the role of structural materials from mere load-bearing systems to lightweight structures with many additional attributes. Short Bio:Nemat-Nasser is a Distinguished Professor of Mechanics of Materials, and has held the John Dove Isaacs Chair in Natural Philosophy (1995-2000) at UCSD, where he has been a faculty member, 1966-70, and Professor and Director of CEAM, 1985-present. As a Professor, he taught mechanics and mathematics at Northwestern University (1970-85). He was awarded the International Technology Institute's Willard Rockwell Medal in 2003, the William Prager Medal in Solid Mechanics by the Society of Engineering Science in 2002, and the ASME Nadai Medal in 2002. He was elected a member of the National Academy of Engineering in 2001, an Honorary Member of the prestigious World Innovation Foundation, in 2004, and an Honorary Member of ASME in 2005. Three times (1994-95, 1996-97, and 2000-01) he has been selected by the graduating seniors as the best teacher of the year; has supervised over 40 Ph.D. students, has authored or coauthored over 400 scientific papers, over 20 books and proceedings; has received ASME's Aerospace Division's Best Paper of the Year Award, Adaptive Structures and Materials Systems [Nemat-Nasser, S. "Micromechanics of Actuation of Ionic Polymer-metal Composites," Journal of Applied Physics, Vol. 92, No. 5 (2002) 2899-2915]; has published two major books: (1) Nemat-Nasser, S. and Hori, M., Micromechanics: Overall Properties of Heterogeneous Solids, Elsevier Science Publishers, 1st edition (1993), 730 pages; 2nd Edition (1999) 810 pages, and (2) Nemat-Nasser, S., Plasticity: A Treatise On Finite Deformation of Heterogeneous Inelastic Materials, Cambridge University Press (2004) 730 pages. His research includes: experimentally-based analytical/computational, nano-scale modeling of response and failure modes of materials, particularly multifunctional structural systems, e.g., structural composites with tunable electromagnetic functionality, thermal management, self-healing, and self-sensing; polyelectrolytes and ionic polymer metal composites as soft-actuators and sensors; shape-memory alloys; bio-hybrid interfaces and their short- and long-term functionality; advanced metals and ceramics; elastomers; granular materials; and hybrid composites. He has been consultant to many companies and has served in a number of national scientific panels. For a complete list of publications and other information, please refer to the website: http://www-mae.ucsd.edu/RESEARCH/NEMAT-NASSER/

Location: Kaprielian Hall (KAP) - rielian Hall, Room 203

Audiences: Everyone Is Invited

Contact: Evangeline Reyes