Please join us November 3rd, for a one-hour talk from Graeme Milton, University of Utah, titled:
Large Guiding Stress: From Pentamodes to Cable Webs to Masonry Structures
Abstract – Pentamode materials are a class of materials that are useful for guiding stress. In particular, they have been proposed for acoustic cloaking by guiding stress around objects, and have been physically constructed. A key feature of pentamode materials is that each vertex in the material is the junction of 4 double cone elements. Thus the tension in one element determines the tension in the other elements, and by extension uniquely determines the stress in the entire metamaterial. Here we show how this key feature can be extended to discrete wire networks, supporting forces at the terminal nodes and which may have internal nodes where no forces are applied. In usual wire or cable networks, such as in a bridge or bicycle wheel, one distributes the forces by adjusting the tension in the wires. Here our discrete networks provide an alternative way of distributing the forces through the geometry of the network. In particular the network can be chosen so it is uniloadable, i.e. supports only one set of forces at the terminal nodes. Such uniloadable networks provide the natural generalization of pentamode materials to discrete networks. We extend such a problem to the limit analysis of compression-only ‘strut nets’ subjected to fixed and variable nodal loads. These systems provide discrete element models of masonry bodies, which lie inside the polygon/polyhedron with vertices at the points of application of the given forces (‘underlying masonry structures’). This is joint work with Ada Amendola, Guy Bouchitté, Antonio Fortunato, Fernando Fraternali, Ornella Mattei, and Pierre Seppecher.
Bio – Graeme Milton received his Ph.D degree in Physics from Cornell University in 1985, and a D.Sc from Sydney University in 2003 based on his book” The Theory of Composites” published by Cambridge University Press, now followed by the book” Extending the Theory of Composites to other Areas of Science”. He is currently a distinguished professor of mathematics at the University of Utah, where he served as department chairman from 2002 to 2005. He has been awarded Sloan and Packard Fellowships, the 2003 SIAM Ralph Kleinman Prize for research bridging the gap between mathematics and applications, the 2007 Society for Engineering Science Prager Medal for contributions to theoretical mechanics, the 2012 Landauer Medal of the ETOPIM association for seminal contributions to the field of composite material science, and the 2015 International prize Tullio Levi-Civita for the Mathematical and Mechanical Sciences. He is a fellow of Society for Industrial and Applied Mathematics. His main interests are in the fields of composite materials, inverse problems.
This one-hour seminar will be presented in the ASRC Auditorium and broadcast via Zoom, with time for Q and A to follow.
Zoom ID: 821 0879 6187
For more information about this hybrid event, please contact:
Leah Abraha
labraha@gc.cuny.edu