Nonlinear effects in a metamaterial with double negativity

Physical phenomena induced by nonlinear effects in an acoustic metamaterial with double-negativity based on two types of scatterers, side holes and membrane, located along a pipe are theoretically and experimentally studied. We find that the pass and forbidden bands related to double-negativity and single-negativity effects in the metamaterial vary with the input acoustic intensities because of the nonlinearities of both types of scatterers. The nonlinearities can disrupt the unique features associated with these characteristic frequency bands of the metamaterial; however, the nonlinear effects may also lead to applications as automatically triggered acoustic isolators, tunable acoustic metamaterials, and so on.