Rigidity of periodic and symmetric structures in nature and engineering

Simon Guest holds the post of Reader in Structural Mechanics, working in the Structures Group of the Department of Engineering at the University of Cambridge.  He did his PhD with Sergio Pellegrino working on novel forms of deployable structures, and has retained an interest in structures that have unusual or unexpected properties.  Much of his work straddles the border between traditional structural mechanics, and the study of mechanisms.  A productive line of research has been an exploration of the effect of symmetry on structural properties, in collaboration with Patrick Fowler.  Simon first worked on the properties of repetitive structures with John Hutchinson, searching for ideal structural forms for shape-changing structures, and showed the interesting property that a repetitive structure, if stiff, must be overconstrained, and hence an apparently 'just' stiff repetitive structure must in fact be flexible.  This work has recently been reinterpreted in the study of zeolites.  He is currently exploring the extension of work on symmetry to include the space group symmetries appropriate for crystal structures.

Patrick Fowler is a Professor of Chemistry at the University of Sheffield, UK. He is interested in the theory, calculation and modelling of electric and magnetic molecular properties, and in applications of graph theory and other mathematical methods in chemistry and beyond, and with special reference to this meeting, applications of group theory to rigidity of engineered and other structures. Topics in chemistry on which he has published include theory and modelling of hydrogen bonding in weak complexes, properties of ions in solids, systematics of the fullerenes, and relations between aromaticity and molecular currents. He is a winner of Corday-Morgan and Tilden medals of the Royal Society of Chemistry and held a Royal Society/Wolfson Research Merit Award 2004-2009. 

Stephen Power is Professor of Mathematics in the Department of Mathematics and Statistics at Lancaster University, UK. He obtained his Bachelor of Science degree from Imperial College, in 1973, and his PhD and DPhil degrees from Edinburgh University, in 1976 and 1990. He has held postdoctoral positions at Dalhousie University and at the California Institute of Technology, and has held visiting professor positions at the Universities of Houston, Alabama, Indiana (Bloomington) and Waterloo. His research in Operator Theory and in Operator Algebras has appeared in two monographs in the Pitman Research Notes in Mathematics Series. His recent research concerns various aspects of the rigidity theory of finite and infinite bond-node frameworks, including bar-joint frameworks constrained to surfaces, the analysis of rigid unit modes (RUMs) in idealized crystal frameworks (New York J. Math, vol  17, 2011), and the theory of general infinite bar-joint frameworks.