"Waves in lattices - opportunities and challenges"
Mathematics, Mechanics, and Materials Unit (Fried Unit) would like to invite you to a Seminar by Prof. A. Srikantha Phani, Department of Mechanical Engineering, The University of British Columbia, Canada.
Date: Wednesday, March 28, 2018
Venue: C016, Level C, Lab1
Anasavarapu Srikantha Phani
Associate Professor of Department of Mechanical Engineering, The University of British Columbia, Canada
Waves in lattices — opportunities and challenges
Architectured lattice materials hold significant promise to realize multifunctional “meta” materials and structures, with wide ranging practical applications from transportation to energy and health areas. This is possible due to our ability to manipulate wave transport, at length scales on the order of and below the wave length, by changing the scattering geometry through topological architecture and material hierarchy.
This presentation will focus on linear elastodynamics of lattice materials in two parts. First, linear elastic wave transport in the bulk and on the edges of a generic lattice will be encapsulated within eigenvalue problems. Different mathematical formulation of these eigenvalue problems will be provided using Bloch theorem. Solutions will be illustrated for typical one and two-dimensional lattices. Wave phenomena unique to lattices, including band-gaps and directionality in dynamic case, will be demonstrated using simulations and experiments. An appealing aspect of these ‘dynamic' eigenvalue formulations is their ability to reproduce ‘static' solutions at zero frequency. St. Venant’s decay of stress from a free edge will be discussed and unusually deep elastic boundary layers will be highlighted in a Kagome lattice in its static response.
In the second part, a practical application problem of vibroacoustic transport in a sandwich panel will be considered where, the elastic waves in the solid interact with pressure waves in the surrounding fluid. Using finite element simulations the advantages of a lattice core will be highlighted. Finally, some challenges arising from the fundamental limitations on achievable wave transport will be briefly mentioned from a feedback theory perspective.
Dr. Srikantha Phani (Srikanth) received his PhD from University of Cambridge in 2004. After a postdoctoral fellowship at Cambridge he worked at University of Bath, UK, before joining the University of British Columbia (UBC) in 2008, where he is now a tenured associate professor. His research interests are in dynamics of materials and structures and mechanics at small scale. His research group strives to marry theory with experiment, where possible. He was awarded Canada Research Chair and Killam teaching prize at UBC.