Investigation of rare earth giant magnetostrictive transducers based on improved LTspice circuit model

Rare earth giant magnetostrictive ultrasonic transducers (GMUTs) hold significant potential for advancement in ultrasonic machining due to their superior properties. Building on the study of a modular multi-field coupled circuit simulation model of the transducer using LTspice, this work further proposes an improved circuit simulation model. By segmenting the transducer components, a segmented equivalent circuit model (SECM) is constructed to reflect the vibration characteristics at different positions within the components. Using this model, a GMUT with a resonant frequency of near 20 kHz for ultrasonic applications (such as ultrasonic machining) is designed. Based on this model, the impedance, bandwidth, axial displacement and stress distribution, displacement nodes, the front-to-rear amplitude ratio, and the amplitude under different excitation currents of the transducer were calculated. The performance of the transducer was also simulated using the finite element method (FEM). Experimental tests showed that the transducer's bandwidth is 225 Hz, the front-to-rear amplitude ratio is 16.40, and the output amplitude is approximately linearly related to the excitation current. When the excitation current is 1.00 A, the output amplitude reaches 6.10 μm, consistent with the results calculated by the proposed model. This demonstrates the accuracy and applicability of the proposed modeling method.