Topological design of mechanical metamaterials

Topological design of mechanical metamaterials
Jayson Paulose, Instituut-Lorentz, Leiden University
Date and time: Thu, Dec 03, 2015 - 11:30am
Refreshments at 11:15am
Location: LGRT 1033
Category: Condensed Matter Seminar
Abstract:
Topological phenomena lie at the forefront of condensed matter physics. When a physical observable is linked to a topological index characterizing a system, it is unaffected by local changes and thus robust against a range of perturbations. This concept of topological protection, originally developed in electronic systems, has recently been applied to mechanical systems as well. In this talk, I'll show how a recent mapping between spring lattices and electronic topological insulators can be exploited to design topologically protected mechanical response in artificial repetitive structures, or metamaterials. First, I'll demonstrate localized flexible regions in otherwise rigid lattices that arise due to an interplay between crystal defects and a bulk topological index characterizing lattice vibrations. I'll then show how topological stress states single out regions for buckling in the interior of a structure. Finally, I'll extend the mapping from central-force spring networks to a broader class of structures with more complex couplings among elements, encompassing gear networks and frictional disc packings. The results will be demonstrated in real-world prototypes of topological mechanical metamaterials, and point towards new ways of designing robust mechanical phenomena across different scales.