Bourns Hall

Colloquium

Sia Nemat-Nasser Distinguished Professor of Mechanics and Materials Department of Mechanical and Aerospace Engineering University of California, San Diego La Jolla, CA 92093-0416 Towards Creating Biomimetic Composites Abstract Multifunctional structural materials possess attributes beyond the basic strength, stiffness that typically drive the science and engineering of the material for structural systems. The structural materials can be designed to have integrated electrical, magnetic, optical, locomotive, power generative, and other functionalities that work in synergy to provide advantages that reach beyond that of the sum of the individual capabilities. Materials of this kind have tremendous potential to impact future structural performance by reducing size, weight, cost, power consumption and complexity while improving efficiency, safety, and versatility. Nature offers numerous examples of materials that serve multiple functions. Biological materials routinely contain sensing, healing, actuation, and other functions built into the primary structures of an organism. In this lecture, I will examine the current state-of-the-art and the challenges that must be met in order to integrate multiple functions into fiber-reinforced polymers to create composites with basic structural attributes that can also perform other functions. I will outline various methods for: Integrating devices and electronic networks into the fibrous composite materials that will empower the resulting structural system: to sense its environment and be self-diagnostic: using integrated electronics and micro sensors; to have tuned and tunable electromagnetic properties and communications signature: incorporating minute amounts of optimally-architectured conductors into the structure of the composite; to be self-healing by reversibly mending micro-cracks at molecular levels: using a new high temperature, processible polymer matrix; to rapidly cool itself: using integrated ultra-fast micro-heat conducting pipes, micro structural moisture evaporation system Integrating devices and nano-particles into surfaces that will empower the resulting structural system: to maintain its surface clean and non-wetting: modifying surface chemistry and morphology to improve aerodynamic efficiency: providing dynamic undulations on surface to harness the environmental energy, effectively store, and efficiently use for various functions. While some elements of this challenging task have been produced and tested, others as well as their integration into a complete product, together with accomponying rules and tools for their effective applications, still remain to be realized, presenting exciting new challenges in engineering sciences. Biosketch Sia Nemat-Nasser, Distinguished Professor in Mechanics and Materials, is a member of the National Academy of Engineering; Life Fellow of ASCE and ASME; Fellow of American Academy of Mechanics (AAM) and Society of Engineering Science (SES); and foreign fellow of the Danish Center of Applied Mathematics and Mechanics. He has been president, vice-president, and director of the SES, and has served as secretary and president of the AAM, and chair of the Materials Division of ASME. He has received the Technical University of Crete's Gold Medal (1997); the 2002 SES William Prager Medal in Solid Mechanics; the 2002 ASME Nadai Medal; the 2003 International Technology Institute's Willard F. Rockwell Medal, and elected honorary member of the World Innovation Foundation. Three times (1994-95, 1996-97 and 2000-01) has been selected by the graduating seniors as the best teacher of the year, and has graduated over 40 Ph.D.’s. Sia has published nearly 420 research articles, a major book (coauthored with M. Hori, 1st ed., 710-page, 1993; 2nd revised ed., 810-page, 1999), and a 730-page treatise in Plasticity, published by Cambridge University Press 2004. A recent paper on electroactive ionic polymer-metal composites [J. Appl. Phy., Vol. 92, 2002, pp. 2899-2915] was awarded by the American Society of Mechanical Engineers (ASME) the 2002 “Best Paper of the Year” in Adaptive Structures and Material Systems. Sia received his BS from Sacramento State (1960), his MS and Ph.D. from Berkeley (1961, 1964), while serving as an assistant professor at Sacramento State (1962-63). His academic career has been at Northwestern University (1964-66, and 1970-85) and at UC San Diego (1966-70, and 1985- present) where he established the Center of Excellence for Advanced Materials, serving as its director since 1987; spearheaded the creation of the Material Science and Engineering Program, serving as its founding director (1989-1994), and held the John Dove Isaacs Chair in Natural Philosophy (1996-2001). Wednesday, April 20, 2005 Bourns Hall A265 10:10 a.m. – 11:00 a.m. (Refreshments will be served at 10:00 a.m.)