[Séminaire DYNAST] Georgios Theocharis « Metamaterials That Change Shape: From Flexible Architectures to Wave-Driven Reconfiguration »

À l’invitation de l’UTR DYNAST, nous aurons le plaisir d’accueillir Georgios Theorcharis (CR CRNS/LAUM, Le Mans Université) le jeudi 3 décembre 2026 à 14h30 à Centrale Nantes (Amphi A) pour une présentation intitulée “Metamaterials That Change Shape: From Flexible Architectures to Wave-Driven Reconfiguration”

Abstract:

How can we design a material that changes shape easily, reversibly, and in a controlled way? I will begin with three families of flexible mechanical metamaterials: cellular solids, origami-inspired structures, and Maxwell lattices. They share a design principle: geometry can allow a structure to deform substantially even when its constituent material strains only slightly.

Flexibility tells us how a structure can deform. Multistability adds a different capability: the structure can settle into several distinct shapes and retain them without a sustained load. A lattice of coupled bistable beams provides a simple model for exploring how these properties affect wave propagation. Small disturbances can travel without changing the configuration, while a larger disturbance can launch a front that leaves a different configuration behind.

I will then contrast two ways of coupling shape change and waves. In a Kresling origami chain, slowly twisting the structure transfers a localized vibration from one end to the other. In a topological Maxwell rotor chain, the roles are reversed: an elastic wave packet can move the boundary between two configurations or create a new one. Together, these examples show how changing the shape can control vibrations—and how vibrations can, in turn, change the shape.