Study On The Magnetoelectric Isotropy Of Terfenol-D/PZT With Nested Ring Structure

In-plane magnetic field measurement has broad application prospects in electrical exploration,aeromagnetic detection,and perimeter safety.The magnetoelectric sensor has outstanding performance in magnetic detection because of its wide frequency response range and high sensitivity.The traditional method of in-plane magnetic field detection is to make two mutually perpendicular single-axis sensors work at the same time,and calculate the final result in the later stage.This not only requires additional circuit support,but also introduces non-orthogonal errors due to inadequate installation accuracy.To solve the existing problems,a magnetoelectric sensor with highly isotropic was designed to achieve direct measurement of the in-plane magnetic field.Firstly,a magnetoelectric composite material based on nested ring structure was designed and prepared.Considering the magnetoelectric property,technological difficulty and manufacturing cost,PZT-5H and Terfenol-D with excellent physical conversion properties are selected as the piezoelectric and magnetostrictive layer.The two kinds of materials with ring structure were nested together by the adhesion of an epoxy resin,and the experimental sample was prepared by vacuuming,pressing,standing,solidifying,and welding.Then,the simulation study of the Terfenol-D/PZT magnetoelectric composite material with nested ring structure was carried out.In this study,the effects of material volume ratio,bias magnetic field and AC magnetic field on the isotropy were studied by finite element simulation software.According to the results of finite element calculation,a theoretical model based on the principle of elastic mechanics was established,and the formula of the isotropic ratio was derived.This can explain the dependence of the isotropic ratio on magnetic field direction,which provids a reference for the following experimental research.Finally,an experimental study on the prepared magnetoelectric materials was carried out.The experimental results showed that the sample has good linearity,and the resolution can reach 0.8nT under resonant frequency and optimal bias magnetic field.The variation of magnetoelectric isotropy with the bias magnetic field and AC magnetic field was basically consistent with the simulation results.In order to achieve miniaturization of the magnetoelectric sensor system,a permanent magnet is used to generate a DC bias magnetic field,and a small-scale experimental device was designed and manufactured by 3D printing technology.After testing,the magnetoelectric isotropic ratio K can reach 3.1.The results demonstrate that the nested-ring structured sensor is highly isotropic.