Midwest Mechanics Seminar

Mechanical Metamaterials

Distinguished Professor Graeme Milton

Composite materials can have properties unlike any found in nature, and in this case they are known as metamaterials. Materials with negative Poisson's ratio or negative refractive index are now classic examples. The effective mass density, which governs the propagation of elastic waves in a metamaterial can be anisotropic, negative, or even complex. Even the eigenvectors of the effective mass density tensor can vary with frequency. We show that metamaterials can exhibit a "Willis type behavior" which generalizes continuum elastodynamics. Non-linear metamaterials are also interesting and a basic question is what non-linear behaviors can one get in periodic materials constructed from rigid bars and pivots? It turns out that the range is enormous. Materials for which the only easy mode of macroscopic deformation is an affine deformation, can be classed as unimode, bimode, trimode,...hexamode, according to the number of easy modes of deformation. We give a complete characterization of possible behaviors of nonlinear unimode materials.

Bio: Born in 1956 in Sydney, Australia, Graeme Milton earned B.S. and M.S. degrees in Physics from the (Australia) in 1980 and 1982 respectively. He earned a Ph.D. degree in Physics from in 1985, and a D.S. from the University of Sydney in 2003. He was a professor at the Courant Institute, New York University from 1987 to 1994. Since then he has been at the University of Utah, where he is currently a distinguished professor of mathematics, and also a chair professor at KAIST Mathematics Research Station, Korea. He is the recipient of a Sloan Fellowship, Packard Fellowship, Ralph E. Kleinman Prize for research bridging the gap between mathematics and applications, Society for Engineering Science Prager Medal for contributions to theoretical mechanics, the ETOPIM Association Rolf Landauer Medal (first competitive award) and is a Fellow of the Society for Industrial and Applied Mathematics (SIAM). He works primarily on composite materials and metamaterials, but also on networks, theories of cloaking, minimization variational principles for wave propagation, Fast Fourier Transform methods for computing fields in composites, and inverse problems, among other things. He is author of the book, "The Theory of Composites", has written over 150 papers, and is currently finishing another book "Extending the Theory of Composites to Other Areas of Science".

Friday, February 26, 2016 12:00 pm - 1:00 pm Room 106 Engineering Research Building Sponsored by the Department of Engineering Physics