Development of a Comprehensive Dynamic Model for Giant Magnetostrictive Transducers Considering Bias Magnetic Field

Giant magnetostrictive transducers (GMTs) featuring high energy density, fast responses, and large output force are playing an increasingly important role in high-power underwater acoustic detection, acoustic sensors, precision actuation, and other fields. However, the presence of strong magnetic bias, eddy current loss, and hysteresis significantly impact the input and output responses of the transducers, making it difficult to effectively reflect the overall nonlinear characteristics of GMT. Therefore, it is crucial to establish a comprehensive dynamic model that can accurately characterize the dynamic behavior of GMT, including different bias magnetic fields, input frequencies, input amplitudes, and time-domain output characteristic. To this end, a comprehensive dynamic nonlinear model, which thoroughly considers the electric, magnetic, mechanical, and their interactions, particularly under the influence of strong bias magnetic field, is developed. First, a magnetic field model is constructed to incorporate both bias magnetic field and ac driving magnetic field. Second, an enhanced dynamic magnetization model is proposed to depict the dynamic magnetization process of giant magnetostrictive material (GMM) rod and the internal distribution of the effective magnetic field, based on the theory of energy conservation. Lastly, a multidegree of freedom (MDOF) dynamic model, considering the distribution characteristics of the GMM rod, is constructed. In order to validate the developed dynamic model, an experimental prototype is produced. The experimental results illustrate that the proposed model is in excellent agreement with the dynamic characteristics of the GMT.