Triggering of transition waves by the collision of solitons or breathers in bistable mechanical metamaterials

It has recently been shown that flexible mechanical metamaterials support a wide range of nonlinear waves, including solitons or breathers. Interestingly, these systems can also be designed to be multistable, thereby enabling them to further support transition waves. In this talk, we analyze the interaction and collision of several types of propagating nonlinear waves in such bistable metamaterials, ultimately leading to the triggering of transition waves (kinks or topological solitons). We analyze in particular the necessary conditions, amplitude, phase of nonlinear waves brought to collision, to trigger transition waves, as well as the influence of localized defects. The numerical simulations and analytical results are completed by experimental demonstrations for several specific cases. Such processes have potentially exciting implications, since they allow the reconfiguration of a metamaterial from one stable state to another, at a distance, and starting from a desired position in the medium. Furthermore, flexible mechanical metamaterials represent a rich platform to test or apply developed models based on bistable nonlinearity and extend our fundamental knowledge on nonlinear wave dynamics.