Study On Size Effect Of Electromechanical Resonant Frequency Of Magneto - Electric Composite

Magnetoelectric (ME) effects refers to the Phenomenon of material in the applied magnetic field under the action of an electric polarization (Magnetoelectric effects) or under the action of applied electric field produces magnetic pole(Inverse magnetic effect). Magnetoelectric effect of magnetoelectric composite material is applied magnetic field made the magnetostrictive phase to produce magnetic force coupling, interface stress transfer through and piezoelectric phase contact force-electricity coupling, caused the piezoelectric phase in the product effect, under the action of magnetoelectricity conversion. Magnetoelectric (ME) materials have been intensively studied for their promising applications in sensors, transducer, filters, oscillators, phase shifters, memory devices and so on.In recent years, the study have found the single dc magnetic field can cause magnetoelectric composite piezoelectric stress and strain. At the same time, the dielectric constant and electromechanical resonance frequency will change. And magnetoelectric composite materials between the ferromagnetic and ferroelectric composite in different ways lead to the magnetoelectric coupling between the stress transfer in a different way, it will inevitably affect the magnetic field of piezoelectric dielectric constants and electromechanical resonance frequency modulation. This article based on the "sandwich layer" and "strip-ring" alien magnetoelectric composite structure to research, the experimental under dc magnetic field is a single magnetic control electromechanical resonance frequency shift rule. By using elastic mechanics model and the piezoelectric and magnetostrictive material constitutive equation, we establish the function relationship between the piezoelectric body capacitance and resonance frequency, the external magnetic field, the parameters of the material and the the size of the material. Through the theoretical model, researching the magnetostrictive phase size of the influence of magnetic control electromechanical resonant frequency offset.These studies choose the giant magnetostrictive material Terfenol-D as a magnetostrictive phase and PZT as piezoelectric phase. In the "sandwich" structure, studied the "layer" between magnetoelectric composite structure is shear stress condition, piezoelectric body volume fraction of magnetron resonant frequency offset, when volume fraction of n=0.4magnetic control frequency offset is greater than the volume fraction of n=0.5.When the magnetic field of100mT, the maximum frequency deviation is 17.7kHz. In the "sandwich" magnetoelectric composite structure, We studied piezoelectric body volume fraction of magnetron resonant frequency and resonant frequency offset influence. When the volume fraction of piezoelectric body n=0.4, with the increase of magnetic field, the resonance frequency and the resonance frequency with the migration phenomenon in a magnetic field, and the resonance frequency with the change of the magnetic field significantly less than the resonant frequency. In the article "the ring" structure, studied the magnetoelectric composite structure is normal stress between cases, magnetostriction loop inside and outside radius ratio on the magnetron resonant frequency offset. Theoretical research shows that when the magnetic field is about H=8.641×10-2T and magnetostrictive ring as the ratio of radius of1.2, the maximum frequency offset is220kHz. Significantly greater than the radius is the radius of1.6times and2times.