Topologically switchable behavior induced by an elastic instability in a phononic waveguide

摘要

While topological insulators have been widely studied, they typically appear in configurations and properties that are set once a structure is fabricated. As such, there is significant interest in developing topologically tunable or switchable concepts. In this work, we demonstrate that geometric nonlinearity in the form of an elastic snap-through instability can be exploited to switch the topological properties of a Timoshenko arch beam unit cell. We first demonstrate that the phonon band structure can be tuned using geometric nonlinearity and large displacement to reveal the existence of a topological phase transition point. To make this concept fully stable under the removal of the applied force, we then demonstrate the emergence of a bistable unit cell by varying the parameters of the unit cell. In doing so, we show that the bistability of the arch beam unit cell can be harnessed to design a switch that controls the topological nature of an interface between two different 1D phononic crystals.