Study On The Structural Design And Magnetoelectric Properties Of Magnetoelectric Laminated Composites

With the development of science and technology,we have put more and more emphasis on the miniaturization and multifunction of devices,which requires us to fabricate multifunctional materials that have two or more functions simultaneously.Magnetoelectric laminated composite is the typical one of them.In this paper,for deeply studying on the magnetoelectric properties of magnetoelectric laminated composites,we designed three kinds of these composites with different structures.Based on homebuilt automatic magnetoelectric testing system,the effect of clamping effect,asymmetric structure and cantilever asymmetric structure on vibration modes and magnetoelectric properties of magnetoelectric laminated composites has been discussed.The main experimental results are as follows:1.According to the magnetoelectric testing theory and sample structure,we designed automatic magnetoelectric testing system with the application of perturbation theory.The system consists of hardware and software part,where the hardware part meets the demand of high-accuracy and high-sensitivity,while for the software part,the automatic testing software has been designed based on Lab VIEW,which has the advantage of improving measurement efficiency and decreasing the error of manual operation.2.We designed magnetoelectric laminated composites,including Terfenol-D/PZT/Terfenol-D(T/P/T),Terfenol-D/PZT(T/P)and Terdenol-D/PZT/Glass(T/P/G),and the effect of single plane clamping effect on vibration mode and magnetoelectric effect of which has been investigated.The results show that there is only length vibration mode for symmetry structure whereas asymmetric one has bend mode and length mode concurrently.Clamping effect can drive the resonate frequency of these two vibration modes toward high frequency and enhance the intensity of first-order bend vibration mode at low resonance frequency.3.Magnetoelectric laminated composite Terfenol-D/PZT/Ni has been designed and the magnetostrictive properties of Terfenol-D and Ni and magnetoelectric properties of Terfenol-D/PZT/Ni with different thickness ratios have been investigated.The results show that Terfenol-D and Ni have positive and negative magnetostrictive property,respectively.The intensity of magnetostrictive of Terfenol-D and Ni is different at various external magnetic field and the magnetostrictive intensity of Ni will increase with increasing of its thickness.When the bais magnetic field is 400 Oe,second-order length vibration intensity and corresponding magnetoelectric coupling coefficient will decline with the increase of thickness of Ni,while first-order bend vibration and length vibration intensity and corresponding magnetoelectric coupling coefficient will increase.The weakest magnetoelectric coupling effect can be reached when the thickness ratio of Terfenol-D and Ni is 1:1 at bais magnetic field is-50 Oe.4.Asymmetric magnetoelectric laminated composite Terfenol-D/PZT/Ni with cantilever structure has been designed,and the effect of thickness ratios of positive and negative magnetostrictive layers on vibration mode and magnetoelectric property has been discussed.The results show that six resonant frequencies can be observed for this kind of structure,including three bend resonant frequencies and three length resonant frequencies.When the bais magnetic field is 400 Oe,second-order bend vibration intensity and its magnetoelectric coupling coefficient will reach the maximum at the thickness ratio of Terfenol-D and Ni is 1:1,the magnetoelectric coupling coefficient is 1.38 V/cm·Oe,first-order bend vibration intensity and its magnetoelectric coupling coefficient decline significantly.While the first-order bend vibration intensity and its magnetoelectric coupling coefficient are the maximum when the thickness ratio of Terfenol-D and Ni is 1:2,the magnetoelectric coupling coefficient is 1.34 V/cm·Oe,the intensity of other resonant peaks decrease obviously.When the bais magnetic field is-50 Oe,the second-order bend vibration intensity and its magnetoelectric coupling coefficient are the maximum when the thickness ratio is 1:1,the magnetoelectric coupling coefficient is 0.78 V/cm·Oe,other thickness is weaker than the magnetoelectric coupling effect.Above experiments are of helpful for designing magnetoelectric laminated composites with stronger magnetoelctric coupling effect,higher stability and less energy dissipation and are of significance for the study of vibration modes and magnetoelectric coupling effect of magnetoelectric laminated composites.