P2I-4 Design and Experimental Characterization of an Composite Longitudinal-Flexural Mode Ultrasonic Transducer

In this work a composite longitudinal-flexural mode ultrasonic transducer is proposed, designed and experimentally characterized. The transducer is composed of a Langevin transducer and of a displacement amplifier, which is composed of a cylinder shaped base with the same section of the Langevin transducer, of four arms, and of a thin disk acting as a displacement collector. The displacement amplifier is designed to convert the almost flat axial displacement provided by the Langevin transducer at its back end into a flexural deformation that produces the maximum axial displacement at the centre of its front end. Analysis and design and of the actuator are performed by using a FEM software. Besides the designed resonance frequency, the vibrational behaviour of the actuator is analysed also at a close frequency, where comparable performance are found. A prototype of the designed transducer is manufactured and experimentally characterized. Measurements of the electrical input impedance and of the displacement on the front surface are presented.