Low-frequency transducer with a periodic displacement amplification structure based on 3D printing

Abstract

The main structure of an underwater acoustic transducer is metallic, and it is fabricated using conventional mechanical manufacturing techniques. Therefore, it cannot adopt complex geometries. Three-dimensional (3D) printing technology solves this problem owing to its ability to manufacture mechanical parts of arbitrary geometry such as closed cavity structures, which can be used to fabricate transducers with complex designs. Therefore, a transducer with periodic displacement amplification structure was proposed. The periodic shell structure of the transducer had a periodic arrangement with a flextensional structure as the basic unit. The structural parameters of the transducer can be adjusted while maintaining the displacement amplification performance. This enabled transducer design according to requirements such as volume constraints for applications in small target platforms. The transducer was manufactured using 3D printing owing to the complexity of the structure. A finite element model of the transducer was established by combining the periodic shell structure with a fixed-size driving vibrator. The dimensions of the transducer were optimized using the finite element method to maintain a higher transmitting voltage response level at a low frequency. Finally, a fabricated and tested prototype with a transmitting response level of 122 dB and resonance frequency of 2400 Hz was obtained. The experimental results demonstrated that the transducer can be used as a low-frequency underwater acoustic source with potential application prospects.