Improved design and manufacturing of low frequency broadband underwater transducers

Wideband low frequency transducers are crucial enablers for building underwater communication networks. The use of low frequencies promises long range communication ranges, but most low-frequency transducers are large, lack directionality and have limited bandwidth. The aim of this study is to tackle these limitations. We take a novel approach at achieving directional radiation: A symmetric driving stack combined with a structure that is tailored to have an asymmetric mechanical response. Tuning the structure to have multiple mechanical resonances allows for an increase in usable bandwidth. Finite element analysis is used to predict the performance of a particular design. The concept is modeled for a shell made out of 3D printable plastic. If the radiation characteristics look promising the shell is then printed. Displacements are introduced in the printed shell using actuators, the resulting vibrations are evaluated in air using a microphone array and Laser Doppler Velocimetry. These concept models can be used to develop transducers made of metals.