No abstract

In this paper, a novel magnetoelectric (ME) composite structure is proposed, and the ME response in the structure is measured at the bias magnetic field up to 2000 Oe (1 Oe = 79.5775 A•m −1 ) and the excitation frequency of alternating magnetic field ranging from 1 kHz to 200 kHz. The ME voltage of each PZT layer is detected. According to the measurement results, the phase differences are observed among three channels and the multi-peak phenomenon appears in each channel. Meanwhile, the results show that the ME structure can stay a relatively high ME response within a wide bandwidth. Besides, the hysteretic loops of three PZT layers are observed. When the frequency of alternating current (AC) magnetic field changes, the maximum value of ME coefficient appears in different layers due to the multiple vibration modes of the structure. Moreover, a finite element analysis is performed to evaluate the resonant frequency of the structure, and the theoretical calculating results accord well with the experimental results. The experiment results suggest that the proposed structure may be a good candidate for designing broadband magnetic field sensors.

In previous works, most of them employ a linear constitutive model to describe magnetocapacitance (MC) effect in magnetoelectric (ME) composites, which lead to deficiency in their theoretical results. In view of this, based on a nonlinear magnetostrictive constitutive relation and a linear piezoelectric constitutive relation, we establish a nonlinear model for MC effect in PZT-ring/Terfenol-D-strip ME composites. The numerical results in this paper coincide better with experimental data than that of a linear model, thus, it’s essential to utilize a nonlinear constitutive model for predicting MC effect in ME composites. Then the influences of external magnetic fields, pre-stresses, frequencies, and geometric sizes on the MC effect are discussed, respectively. The results show that the external magnetic field is responsible for the resonance frequency shift. And the resonance frequency is sensitive to the ratio of outer and inner radius of the PZT ring. Moreover, some other piezoelectric materials are employed in this model and the corresponding MC effects are calculated, and we find that different type of piezoelectric materials affect the MC effect obviously. The proposed model is more accurate for multifunction devices designing.

Aiming at the coupling simulation problem that ignores the acoustic structure boundary in the traditional acoustic suspension simulation, based on the magnetostrictive effect, the piezoelectric effect, and the acoustic-structure coupling model, this paper uses a magnetoelectric structure composed of the magnetostrictive material Terfenol-D and the piezoelectric ceramic PZT-5H. The composite material is used as, and the magneto-electric-acoustic fully coupled model of the magneto-electric composite material is established and compared with the one-way coupling model; The particle levitation of magnetoelectric composite materials in the multi-field coupling environment of the magnetic field, electric field, sound field, and displacement field was simulated and calculated; the influence of different widths of magneto-electric composite materials and the size of the resonant cavity on the effect of acoustic levitation was analyzed, and the best results were obtained. The geometric parameters required for optimal suspension are analyzed; the sound pressure output performance of the overall magnetoelectric composite ultrasonic suspension device under the optimal size and the judgment of the suspension position is analyzed, and I displayed the good suspension of the simulated particles in the sound field visually. The research results show that the difference in the amplitude output of the transducer will affect the sound pressure output performance of the transducer, and there is a large error in the one-way coupling; the magnetoelectric composite material can be used as an ultrasonic transducer to achieve acoustic suspension, and suspended particles It shows a good acoustic levitation effect in the simulation. The fully coupled simulation of ultrasonic transducers and the research on such ultrasonic transducers can open new ideas for the research and development of new ultrasonic transducers in the future.