Experimental And Finite Elementanalysis Of The Vibration In Magnetoelectric Structure

A magnetoeleric energy harvester is a collector of energy. It can harvest the energy of allsurroundings which is transformed into electric energy for the micro-elctronic system. Theharvesting devices which is laminated by the magnetostrictive material Terfenol–D andpiezoelectric material can manufacture energy collectors of various structures (PMP、 MPM).The harvesting system is made up of permanent magnet, harvesting device and Helmholtz coils.The magnetostrictIve layer of harvesting devices is magnetized by its length, and piezoelectriclayer is polarized by its thickness. Both Terfenol-D and PZT work in the pattern of extensionalvibration, harvesting devices is in the alternating magnetic field of Helmholtz coils, and theelectromagnet which is in either ends of Helmholtz coils provides the device with bias magneticfield. The alternating magnetic field of Helmholtz coils changes the internal magnetic field ofTerfenol-D of harvesting devices to bring about the strain of magnetostrictIve layer which transfersto PZT, in order to get the response to electric charge of the surfaces of piezoelectric layer; andthen, electric output is produced and the transformation of magnetic field energy-mechanicalenergy-electric energy is realized finally.On the premises of placing the laminate in the free boundary, the study clarifies therelationship among Magnetoelectric coupling coefficient, load impedance, frequency andmagnetoelectric voltage conversion coefficient. Meanwhile, the study also illustrates therelationship of energy density, energy exchange efficiency and load impedance and draws therelation schema by the given parameters.The study is about a model analysis of magnetoelectric effect of the laminated structure by thereengineering of the software Comsol, which possesses a user-defined function of PDE. In thestudy, we have constructed the finite element model and calculated that the high order harmonicfrequency and magnetoelectric voltage conversion coefficient of the test specimen are inaccordance with the experimental results approximately by the input of geometric model, customequation, the setting of material parameter and boundary conditions, and the partition of griding.In the experiment of the study, we have manufactured the harvesting devices with laminatedstructure, constructed the harvesting system of magnetoelectric effect and tested themagnetoelectric voltage conversion coefficient of the specimen. It is proved that the finite-elementanalysis manages to indicate the variation trend of resonant frequency and magnetoelectricityvoltage conversion of the specimen accurately and offer a foundation to the following design and promotion of the structure by the experimental dates and results. The study has concluded that theoptimal bias magnetic field of the test specimen is in300Oe-450Oe.