Low-frequency, FSMA/piezo transducers

Ferro Soluitons, MIT and Image acoustics propose to develop a Low-frequency hybrid transducer. Ferromagnetic shape memory alloy (FSMA) Ni_Mn-Ga crystals have greater energy density than Terfenol-D or piezoelectric materials. FSMAs have a good acoustic impedance match to water. Thus, low-frequency FSMA-based transducers can be significantly smaller than their competitors. Ferro solutions showed in Phase I that acoustic excitation of Ni-Mn-Ga dramatically increased the efficiency of magnetic actuation: acoustic assist more than doubled the low-frequency, low-field output compared to actuation without acoustic assist. This was demonstrated in a commercial FSMA actuator modified with a piezo stack. A new class of acoustic-assisted FSMA-based actuators was designed and modeled, indicating potential for superior performance as low-frequency transducers suitable for UUV or sonobuoy applications. In Phase II the database of acoustic parameters of new, higher-quality Ni-Mn-Ga crystals is expanded. The design of compact, hybrid transducers is refined with Image Acoustics proven software using new magnetoelastic data. Subcomponents of the transducer designs will be fabricated and tested in air at Ferro Solutions. Results will inform next-stage transducer designs for manufacture and water testing at Massa, Inc. Results will be analyzed and discussed with Navy advisors for transition and specified applications.