Active structural acoustic illusions

We present active manipulation of the structural vibrations of an elastic body to generate an acoustic illusion. The resultant illusion misrepresents the nature, size and number of objects in the exterior acoustic domain. We demonstrate our technique, herein termed active structural acoustic illusion, using an elastic cylindrical shell. The radial motion of the shell at its cavity resonance frequencies is actively modified using localised mechanical forces. Acoustic illusions are generated to resemble the scattered acoustic field by one or more rigid cylinders of different size and location.