Dynamic Simulation And Experimental Study On Vibration Characteristics Of Mre Cantilever Sandwich Beam Under Non-homogeneous Magnetic Fields

Magnetorheological elastomer(MRE)is a new branch of smart material magnetorheological materials,MRE is a solid simulation of magnetorheological fluid(MRF),it is mainly composed of high molecular polymer(such as rubber)and additives.MRE has the advantages of MRF and elastomer at the same time,and it also solves the shortcomings of the MRF,such as easily settlement and poor stability which are limit the development of MRF.Therefore,MREs have more potential for engineering applications than MRFs,it has a good application prospect in the field of semi-active vibration control of structural vibration.Put MRE into the structure of sandwich beam,the control of structural vibration characteristics can be realized by changing the strength of the applied magnetic field.But at present,the studies on the dynamics of the MRE are mainly studied under the uniform magnetic field,and the studies on the dynamics of the non-homogeneous magnetic field are rare.In this paper,MRE with different content of silicone oil were prepared,and the rheometer was used to test the rheological properties of the MRE,make the analysis of relationship between shear modulus,loss modulus and magnetic field strength.The results show that the shear modulus and the loss modulus of the MRE increased with the increment of the applied magnetic field strength,and the shear modulus and the loss modulus of the MRE with high content of silicone oil are larger.Then the MRE is considered as a linear viscoelastic material,dynamic model is established by using the finite element method and the vibration equation is developed,the numerical simulations are made to investigate the natural frequency change regulation under non-homogeneous magnetic fields.The MRE sandwich beams with different content of ferromagnetic particle,oil content and different thickness of magnetorheological elastomer layer,the experiment test rig was set up to investigate the vibration characteristics of the MRE sandwich cantilever beams under non-homogeneous magnetic fields.The natural frequency is analyzed and the results are compared with the numerical simulation results.In this paper,the numerical simulation results and experimental results show that variation trends of the natural frequency of the MRE cantilever beams are basically same.The results show that the first natural frequency of the MRE sandwich beams decreased with the increment of the applied magnetic field strength,showing the MRE sandwich beams had the capabilities of left shifting first natural frequency,and the results also shows that the first natural frequency of the MRE sandwich beams decreased as the magnetic field that applied onthe beams was moved from the clamped end of the beams to the free end of the beams.The first natural frequency of the MRE sandwich beams with high content of ferromagnetic particles or high content or large thickness of the magnetorheological elastomers are correspondingly smaller.