Fracturing of topological Maxwell lattices

In this talk, we will present our research on how topologically polarized Maxwell lattices fracture when they are stretched by applied stress. Maxwell lattices are mechanical structures containing equal numbers of degrees of freedom and constraints and are thus on the verge of mechanical instability. Recent progress in topological mechanics leads to the discovery of topologically protected floppy modes and states of self-stress at edges and domain walls of Maxwell lattices. We find that applied stress on topological Maxwell lattices is attracted by state-of-self-stress domain walls, and the lattice will gradually fracture at these domain walls first. We will explain the results using topological mechanics and further discuss how these domain walls protect the rest of the structures against cracks. Our results lead to possible designs of new mechanical metamaterials that exhibit high strength against fracturing and well-controlled fracturing process.