Study On The Magneto Electric Properties Of Graphene/Silicone Rubber Based Magnetorheological Elastomers

As a new type of intelligent material,the characteristic properties of MREs mainly include the mechanical and electrical properties under magnetic control.At present,the MREs are mainly used as sensing actuators in the field of intelligent integrated component,but the poor conductivity and dielectric properties of traditional magnetorheological elastomers greatly limit their development.In order to solve these problems mentioned above and improve its magnetoelectric properties,a kind of silicon-rubber-based MREs added with graphene(GR/RTV MREs)is proposed in this paper.The magnetoelectric properties of Gr / RTV MREs are studied by simulation,numerical model and experiment.The main contents of this paper are as follows:Firstly,the simulation of the magnetoelectric characteristics of Gr / RTV MREs is carried out.Based on the micromechanics method and the equivalent modulus,the multi-scale simulation analysis of the magnetoelectrical properties of MRE with different graphene volume fraction is carried out by using COMSOL,and the pressure resistance curves under different magnetic induction intensities are obtained.The results show that the conductivity of Gr / RTV MREs increases with the increase of graphene's volume fraction.Secondly,the magnetoelectrical model of Gr / RTV MREs is established.To describe the magnetron piezoresistive characteristics of GR/RTV MREs,a magnetron piezoresistive model for describing material resistance,magnetic field and external pressure is established based on Fowler-Nordheim formula and magnetic dipole model.To describe the relationship between initial resistance and graphene content in the model,a conductivity model suitable for GR/RTV MREs is established based on the general effective medium equation,and the relationship curve between conductivity and graphene volume fraction was obtained by numerical calculation.According to the analysis curve,with the increase of the volume fraction,the influence of graphene on the electrical conductivity of materials decreases from strong to weak,and finally approaches zero.Then,the preparation of Gr / RTV MREs with different graphene volume fraction is completed.The preparation of Gr / RTV MREs with the volume fraction of graphene 0,3%,6%,9%,12%,15% is prepared by solution blending method.The morphology of the samples is observed by SEM.The results show that the surface of the sample is smooth and smooth,there is no air hole in the sample,the conductive chain of ferromagnetic particles is clear and complete,and the content of each element is consistent with the expectation.At last,the experiment of the pressure resistance of Gr / RTV MREs under different magnetic induction fields is completed.An experimental device is set up to test the pressure resistance of MREs under 0-120 m T magnetic fields.The experimental results show that when the volume fraction of graphene is less than 12%,there is a significant positive correlation between the magneto piezoresistive properties and the volume fraction of graphene;when the volume fraction of graphene is more than 12%,the increase of graphene content has little effect on the electrical properties.At the same time,when the magnetic induction strength is more than 80 MT,the effect of magnetic field on the pressure resistance of MRE tends to be zero.Based on the experimental data,the model of magnetron resistance is modified to verify the validity and accuracy of the theoretical model.