DIRECTIONAL FLEXTENSIONAL TRANSDUCER

A 3.25-kHz directional class IV flextensional transducer, which produces enhanced motion on one surface and canceled motion on the second surface, has been developed. The transducer radiating surface consists of a thick-walled oval aluminum shell. A Navy type III piezoelectric ceramic stack with two active sections and one inactive section is used to drive the shell along its major axis into its directional mode of operation. The directionality is achieved by exciting the drive stack into both extensional and bending modes. Both measurements and a finite element analysis on this device showed the center portion of one side to be moving at a relative displacement level more than 20 dB greater than the corresponding center portion of the other side.