Errors are everywhere, and mechanical failures are especially common: buckled grain silos and cracked support columns are, justly, seen as an issue to be avoided. But flaws can also be used to... Show moreErrors are everywhere, and mechanical failures are especially common: buckled grain silos and cracked support columns are, justly, seen as an issue to be avoided. But flaws can also be used to design materials with unique functionalities. In the work presented here, we use two types of imperfections to create functional structures. First, we design materials that are locally stiff or soft, depending on how they are actuated, using topological imperfections: mistakes in their underlying architecture. Second, we create structures that shape-morph, because their individual elements fail, buckle, and snap- features that should be avoided otherwise. Show less
In mechanical metamaterials, large deformations can occur in systems which are topological from the point of view of linear waves. The interplay between such nonlinearities and topology affects... Show moreIn mechanical metamaterials, large deformations can occur in systems which are topological from the point of view of linear waves. The interplay between such nonlinearities and topology affects wave propagation. Beyond perfectly periodic systems, defects provide a way to modify and control the properties of metamaterials, and can also interact with both nonlinearities and the bulk topology. To investigate these, we explore the wave propagation in three mechanical models, i.e.~solitary waves in topological rotor chains, lattice waves in twisted kagome networks, and transverse shock waves in flexible strings. Show less
