Magneto-Mechanical-Thermal-Electric Multi Field Coupling Characteristics And Device Performance Of Laminated Magnetoelectric Materials

Laminated magnetoelectric composites,which are prepared by combining magnetostrictive materials and piezoelectric materials,have attracted extensive attention from researchers in many fields and disciplines due to their strong magnetoelectric conversion ability at room temperature,simple preparation,high sensitivity and fast response.Laminated magnetoelectric composites are new advanced functional materials with wide application value.They are widely used in magnetic field/current sensors,energy collectors,magnetoelectronic microwave devices,magnetoelectronic storage and new antennas.In recent years,many researchers at home and abroad have conducted in depth and systematic research on the experimental,theoretical and simulation of magnetoelectric composites.However,most of the previous theoretical analysis models and finite element models can not well describe the nonlinear magnetoelectronic coupling effects of magnetoelectric composites in complex environments such as different bias magnetic fields,different temperatures and different pre stress.Therefore,it is necessary to propose a multi physical field coupled finite element model which can accurately describe the magnetoelectric effect of magnetoelectric composites and take full account of the material's nonlinear characteristic.In addition,the design and application of energy collectors based on magnetoelectric materials still need further study,such as,how to improve the energy collection performance of the energy collector,achieve broadband multi-frequency and the collection of multi field energy.Based on the above research background,this paper will do the following research:Firstly,by adopting the nonlinear constitutive equation of magnetostrictive materials and the linear constitutive equation of piezoelectric materials,the nonlinear magneto-mechanical-thermo-electric coupled finite element models of TerfenolD/PZT/Terfenol-D and Ni/PZT/Ni laminated magnetoelectric structures are established.The magnetoelectric coefficients of the laminated magnetoelectric structures are calculated respectively in the case of coupling stress and without coupling stress.The results show that the predicted values of the magnetoelectric coefficients of the two laminated magnetoelectric structures at different temperatures are in good agreement with the experimental data under low,intermediate and high magnetic fields.The magnetoelectric coefficients under the coupling stress are smaller than those without the coupling stress.Coupling stress has a great influence on the magnetoelectric coefficients of Terfenol-D/PZT/Terfenol-D laminated magnetoelectric structures,but has little effect on the magnetoelectric coefficients of Ni/PZT/Ni laminated magnetoelectric structures.In addition,the distribution characteristics of flux density,displacement and voltage of laminated magnetoelectric structures under different temperatures and prestress conditions are studied in detail.The sensitivity of magnetoelectric coefficients to temperature and prestress can be adjusted by prestress and temperature respectively.Specifically,increasing temperature can reduce the sensitivity of magnetoelectric coefficients to prestress and improve the stability of magnetoelectricity devices in complex environment.Then,in order to improve the energy collection efficiency of the energy collector and realize the simultaneous collection of multi field/multi frequency energy,a mechanical/magnetic dual energy collector with magnetic-mechanical-electric conversion is designed in this paper.Generally speaking,mechanical vibration and magnetic field exist at the same time in our daily life.For example,the large motors commonly used in industrial manufacturing,mechanical vibration caused by rotor rotation and stray magnetic field produced by motor coil exist at the same time.However,the frequency of mechanical vibration is usually different from that of magnetic field.How to collect the energy of these different frequencies and fields at the same time is a very important research content.The results show that the first order resonance voltage is larger than the second order resonance voltage when mechanical energy is collected separately,and the second order resonance voltage is larger than the first order resonance voltage when magnetic energy is collected separately.Therefore,mechanical and magnetic dual energy collection at different frequencies can be realized by using the first and second resonance modes of cantilever beam structure to collect mechanical and magnetic energy respectively,it also maximizes the efficiency of energy collection.The voltage has a linear superposition effect when mechanical energy and magnetic energy are collected at the same time,while the power of two excitations acting simultaneously is greater than the superposition of two excitations acting alone.The above results can provide some help for the design and application of multi field/multi frequency energy collectors.Finally,the magnetic-mechanical-electric energy collector of cantilever beam is systematically studied in this paper.Emphasis is placed on the influence of the direction of AC magnetic field and the position or number of permanent magnets on the energy collection performance of the magnetic field energy collector,then,the other factors affecting the energy collection performance of magnetic field energy collector are analyzed,such as structure size,base material,etc.In addition,some experimental studies have been carried out on other applications of cantilever beam energy collector,such as the collection of rotational energy of fan.The experimental results show that the energy collection efficiency can be improved by a series of optimal design of the cantilever beam energy collector.All in all,the numerical analysis of laminated magnetoelectric composites is carried out in this paper,and the nonlinear multi field coupling magnetoelectric effect of laminated magnetoelectric composites has been improved and further developed.At the same time,the finite element analysis model of mechanical/magnetic dual energy collector is constructed,and the cantilever beam energy collector is experimentally studied.The research results are expected to provide some guidance for the development,design and application of functional devices based on magnetoelectric composites.