- Mechanical Behavior of Materials
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 weight make them attractive for structural sandwich panels, their ability to undergo large deformations at relatively low stresses make them ideal for absorbing the energy of impacts, their low thermal conductivity make them excellent insulators, and their high specific surface area make them attractive for substrates for catalysts for chemical reactions. Cellular materials are increasingly used in biomedical applications. Open-cell titantium foams are being developed to replace trabecular bone. Porous scaffolds for regeneration of damaged or diseased tissues often resemble an open-cell foam. Cellular materials are also widespread in nature in plant and animal tissues: examples include wood, cork, plant parenchyma, trabecular bone and lung alveoli.
Our group has contributed to the understanding of the mechanics of cellular solids, as well as to their use in many of the above applications. Recently completed projects include: the design and characterization of osteochondral scaffolds for the regeneration of cartilage as well as the underlying bone; the mechanics of fluid flow through open-cell foams for protection from impacts; and low thermal conductivity aerogels for building applications. Current project include: structural bamboo products and the mechanics of balsa and balsa-inspired engineering materials.