Many materials have a cellular structure, with either a two-dimensional array of prismatic cells, as in a honeycomb, or a three-dimensional array of polyhedral cells, as in a foam. Engineering honeycombs and foams can now be made from nearly any material: polymers, metals, ceramics, glasses and composites, with pore sizes ranging from nanometers to millimeters. Their cellular structure gives rise to a unique combination of properties which are exploited in engineering design: their low weights make them attractive for structural sandwich panels, their ability to undergo large deformations at relatively low stresses makes them ideal for absorbing the energy of impacts, their low thermal conductivity makes them excellent insulators, and their high specific surface areas make them attractive for substrates for catalysts for chemical reactions. Cellular materials are also important in medicine. In patients with osteoporosis, the two most common fractures are of the hip and spine, both of which have large amounts of spongy or trabecular bone. And porous scaffolds for regeneration of damaged or diseased tissues often resemble an open-cell foam. Cellular materials are also widespread in plant tissues, including wood, cork, bamboo and plant stems and leaves. This talk reviews the structure, mechanical behaviour and applications of a broad range of cellular materials.
Professor Lorna Gibson is an alumna of the Department of Civil Engineering at the University of Toronto and is currently the Matoula S. Salapatas Professor of Materials Science and Engineering at MIT. Professor Gibson studies the mechanical behavior of materials, specializing in materials with a cellular structure, such as engineering honeycombs and foams, scaffolds for regenerative engineering, and natural materials such as wood, bamboo and plant leaves and stems. She is the co-author of Cellular Solids: Structure and Properties (with MF Ashby), Metal Foams: A Design Guide, (with MF Ashby, AG Evans, NA Fleck, JW Hutchinson and HNG Wadley) and Cellular Materials in Nature and Medicine (with MF Ashby and BA Harley).
Current research projects include: balsa as a model for bioinspired design of engineering materials and the mechanics of structural bamboo products, analogous to wood products such as oriented strandboard. Professor Gibson was recently named a MacVicar Faculty Fellow, MIT’s top award for undergraduate teaching. She has served as Chair of the Faculty and Associate Provost at MIT.