Design Principles for Active Solids

: (Alternative Format Thesis)

Abstract

In almost any area of human technology, functionality is limited by material properties: a glass window is transparent but fragile, a paper bag is flexible but not shock-absorbent, a concrete structure can support tons of weight but may crumble from swaying. Metamaterials aim to ameliorate these trade-offs by manipulating the microstructure of conventional materials in such a way that novel functionality emerges. Even more fundamental is the stark difference between the typical man-made immobile substances that deteriorate over time, and biological matter that can grow, regenerate, and move. Active matter takes a first step towards emulating these autonomous and self-organising properties by embedding energy-expending elements within conventional artificial media. This thesis presents a wide variety of metamaterial designs, ranging from air hole distributions in optical fibre, beam orientations in slender 3D-printed lattices, chiral activity in fluids of spinning particles, to communicating motorized linkages in model active solids. The common thread across these designer materials is the emergence of a topological or an odd response. The former is characterized by robust excitations at material boundaries, whereas the latter relates to fluids with non-dissipative viscosity, and to elastic solids that can autonomously and continuously perform tasks that cost the material energy. We discuss the design principles that are required or desired for these exotic behaviours and investigate the consequences for material functionality.

Date of Award	11 Oct 2023
Original language	English
Awarding Institution	University of Bath
Supervisor	Anton Souslov (Supervisor) & Paul Milewski (Supervisor)