ACOUSTICALLY ACTIVE SURFACES USING PIEZORUBBER

The use of single and double layers of piezoelectric material to form acoustically active surfaces for the elimination of reflected and transmitted waves is first discussed from a theoretical standpoint. Experiments are then described in which the piezoelectric composite piezorubber is used as the transducing material in single and double layer active surfaces. It is demonstrated that with the single layer, either reflection or transmission can be eliminated, while both reflection and transmission can practically be eliminated with the double layer. The electrical driving signals applied to the active surfaces in order to accomplish this are shown to agree well with theoretical models using material parameters for piezorubber determined from impedance measurements.